The Engineering Projects

Smart Buildings Boost the Need for Intelligent Gas Sensors

The global smart building market is expected to reach approximately $33.5M by 2022, indicating a vastly growing need for safe and secure building environments. These sensors continuously monitor environments to ensure that the air quality, temperature, and ventilation in a building are accurate. They can identify scores of potential threats - including harmful gases and gas leaks. According to one recently published report, the need for more sophisticated and intelligent gas sensors in the smart building of the automation industry is critical - this is because consumers demand security where tighter governmental regulations are calling for better and safer indoor air quality.

How Gas Sensors Improve Building Safety?

Gas sensors play a vital role in building safety. They are designed to detect and monitor gas leakage and toxic gases. This is achieved through safety inspections that focus on testing air quality in different parts of the building. New health and safety regulations passed by governments across the globe mean that gas sensors boasting high sensitivity to gases are becoming an important part of safety systems.

These sensors are electronic devices with the ability to detect the existence of (and particular concentrations of) different gases in the environment. Based on the concentration of gases in the atmosphere, the sensors show the different resistance levels of various substances used in the device to check for fluctuations in output voltages. Depending on the readings obtained, we can identify the type and concentration of different gases.

What Type of Gas Sensors Are Used in Engineering?

Gas sensor technologies are used to boost engineering safety - including non-dispersed infrared sensors for carbon dioxide detection and miniaturized photo-ionized detectors for measurement.

In the past, buildings used to contain different sensors, occupying significant space. A need has therefore arisen for more compact, robust, powerful, and reasonably priced sensors that can ensure safety in different sectors - including the health, oil, gas, and automation industries.

Detecting Combustible Gases

Modern-day gas sensors can detect a wide array of gases - including combustible gases such as methane, butane, propane, hydrogen, and more. These sensors can detect the presence of toluene, ozone, nitrogen dioxide, and other gases, offering a reading in the range of 0 to 5 parts per million.

The components used in the sensors can respond to changes in physical or chemical properties. The latter is converted to electric signals by transducers; the sensors measure the concentration of different gases through analytic reactions between the sensing material and target gases. Various types of sensors exist; for example, optical gas sensors measure the amount of light scattering caused by different type of gases. The type of sensor used depends on its intended application. For instance, catalytic sensors are better and therefore preferred for combustible gas detection, while carbon nano-materials are usually chosen for environmental monitoring. These materials have different advantages as well in terms of sensitivity, cost, response time, weight, and stability.

New Chemistry for Ultra-Fine Gas Sensors

Engineering teams are constantly on the lookout for more efficient, lighter sensors capable of fulfilling more than one role. On July 1, 2020, scientists from Ruhr-University Bochum announced that they had developed a new process for zinc oxide layers that can be utilized both ways i.e. as a protective layer on plastic and for sensing the presence of toxic nitrogen gas. These layers can be laid down via atomic layer deposition, which contains chemical compounds (or precursors) that ignite when they come in direct contact with the air. The Ruhr-University Bochum team created a new manufacturing process using a non-pyrophoric zinc precursor that can be made at temperatures that are low enough for plastics to be coated. These zinc oxide layers can do many functions all in one fell swoop - including that of protecting degradable goods.

How are Ultra-Thin Zinc Oxide Layers Made?

In the manufacture of sensors for nitrogen dioxide, a fine layer of nanostructured zinc oxide is applied to a sensor substrate that is then joined to an electric component. The Ruhr-University Bochum scientists have used atomic layer deposition (ALD) to join the ultra-fine layers to the sensor substrates. ALD processes are usually used in engineering to make tiny electrical parts using ultra-thin layers. Some are just a few atomic layers thick, yet they are robust and highly efficient. For this process, specific precursors that can form such fine layers are required. Up until now, these layers were made using highly reactive, and highly pyrophoric zinc precursors via ALD.

Working in a Safer Fashion

The new method allows teams to work safely by avoiding highly ignitable compounds. It relies on very safe, low temperatures that enable the deposition of the layers onto plastic. It is therefore of great use in the production of gas sensors as well as in any industry in which goods need to be protected from oxidation through the use of plastics. The food and pharmaceutical industries are two sectors that can potentially benefit from these gas-protected plastic layers. The gas sensor market is predicted to grow exponentially every day. Continuous monitoring of gas levels is key to ensuring the health and safety of those living and working in buildings where they need to deal with toxic and sensitive gases every day. Trends dominating this product include a need for greater customization, lower-cost sensor technology, and smaller-sized sensor packages. Due to the high demand for smart buildings over the years, the desire for continuous and accurate gas measurement is increasing daily. These sensors are high in demand in different areas including the Asia Pacific Region, the Middle East, and North America. Moreover, several new chemical processes are required for the creation of ultra-thin and efficient gas sensors.

This is achieved by atomic layer deposition using precursors that require low heat and can protect the integrity of the plastic. A small amount of fine nanostructured zinc oxide is applied to a sensor substrate before connecting it with an electric component. This new intelligent gas sensor technology is used in the gas and packaging industries.

New Proteus Libraries of Digital Sensors

Hi Everyone! Hope you’re well today. I welcome you on board. In this post today, I’ll walk you through the list of New Proteus Libraries of Digital Sensors.

I told you earlier, our team has designed these proteus libraries after a lot of hard work and you won’t find them anywhere online. We are designing these proteus libraries to help you better understand the working of sensors through proteus simulations. Also, we have added the interfacing of these sensors with Arduino boards, where you can observe the working and simulation of sensors with microcontrollers or Arduino Boards.

If you think we are missing something important, something that should be a part of the Proteus library, share your valuable suggestion in the comment section below, and I’ll try my best to design and add the respective library in Proteus.

Adding a new library is simple and straightforward. Even you can do it on the fly. Read this post on how to add a new library in Proteus.

Before I bore you to tears, let’s jump right in and look for the New Proteus Libraries of Digital Sensors.

I hope you’ve already got Proteus installed in your system. If you haven’t, read this post on how to download and install Proteus Software.

Keep reading.

1. PIR Sensor Library for Proteus

PIR stands for Passive Infrared Sensor which is mainly used for motion detection. It makes use of infrared radiation for motion detection. PIR sensor contains crystalline material at the face of a sensor that detects infrared radiation. The infrared rays are reflected from the object, generating heat and infrared radiation in its field of view. This sensor is used for both domestic and industrial applications for security purposes.

We’ll include TestPin for motion detection in proteus simulation. The sensor doesn’t carry this pin in real. HIGH and LOW voltages generate a sense of motion detection. When the voltage is HIGH it means TestPin is getting 5V and in this case, it will detect the motion when the pin is LOW it means there is no voltage and thus no motion is detected.

Download PIR Sensor Library for Proteus

2. Gas Sensor Library for Proteus

Gas sensor, as the name suggests, is used to measure the presence of gages in the atmosphere. The concentration of the gas in the surroundings changes the resistance of the sensor material, ultimately generating a corresponding potential difference. When this potential difference is measured as an output voltage it gives the amount of concentration of gas in the atmosphere.

These sensors are mainly installed for the detection of toxic gases and gas leakage. When it detects the gas leakage, it sends an alarm signal, confirming there’s a leakage in the surrounding that needs to be fixed. Gas sensors vary in terms of their range, size, and sensing ability. It all depends on the nature of the application and the gas used. They mostly operate as a part of an embedded system that is commonly connected to the audible alarm.

We’ve produced both: simple simulations with the gas sensor and the simulation of the sensor with the Arduino Board. You can click the link below to download the proteus library of the gas sensor.

Download Gas Sensor Library for Proteus

3. Flame Sensor Library for Proteus

Sensitive to normal light, a flame sensor is used to detect fire and flame. The flame sensor carries a range from 760nm to 1100nm. Better maintain a certain distance from the fire or flame object, or else high temperature might damage the sensor. A distance of almost 100cm from the flame object is normally recommended. These sensors are embedded in firefighting robots as a part of an embedded system. Moreover, they work better than the smoke sensor due to their remarkable sensitivity. The flame detection mechanism includes a natural gas line, alarm system, and fire suspension system. This flame sensor is widely used in industrial boilers, confirming if the boilers are working properly.

Again, we’ve included both: simple simulation and simulation with the Arduino board. The Proteus library zip file download link is as follows:

Download Flame Sensor Library for Proteus

4. Vibration Sensor Library for Proteus

A vibration sensor, also known as a piezoelectric sensor, is used to measure the vibration of the machines. Vibration plays a critical role in the working of industrial machinery. The values exceeding the recommended values can put the entire system at a total halt. These sensors are installed in industrial machinery to keep the vibration under control. They are mainly connected to the audible alarm system which results in total suspension of the system in case vibrations exceed a certain number.

Vibration sensors use the piezoelectric effect to monitor minor changes in temperature, pressure, acceleration, and force. Thus detecting the changes converts them into an electrical signal. These sensors are also used to monitor air fragrance. It differentiates between fragrances by measuring both quality and capacitance.

We’ve added the proteus library of the vibration sensor. Curious to download and use this proteus library? Click the link below.

Download Vibration Sensor Library for Proteus

5. Flex Sensor Library for Proteus

A flex sensor, also known as a bend sensor, is a device used to measure the value of a bend. This sensor is attached to an exterior that upon twisting produces a change in resistance in the sensor. It finds applications for indoor sensors, robot whisker sensors, Nintendo power gloves, and stuffed animal toys. These sensors are composed of carbon or plastic material that provides enough elasticity to the sensor where the value of deflection is directly related to the varying resistance. Flex sensors are mainly divided into two types based on their size and varying resistance i.e. 2.2-inch bend sensor and 4.5-inch bend sensor.

We’ve designed and added both: simple simulations of the flex sensor and simulations with the Arduino board. The Proteus library zip file download link is as follows:

Download Flex Sensor Library for Proteus

6. Rain Sensor Library for Proteus

A rain sensor, as the name suggests, is a device used to detect rainfall. It operates on the principle of total internal reflection. A rain sensor is mainly used in two applications. In the first case, it is used to protect the car interior from rain. The sensor uses infrared light that is flashed at an angle of 45 degrees on the windscreen. When the screen is wet, this angle changes to 60, causing the light to reflect with a lower intensity than automatically activates the car windscreen wipers to remove water and clean the car windscreen.

In the second case, the water conservation device is attached to an irrigation system that brings the system to a total halt in the case of rainfall. These sensors for irrigation systems come in both hard-wired and wireless versions.

You can download the rain sensor library for Proteus from the link below. Both simple simulation and simulation with the Arduino board are available.

Download Rain Sensor Library for Proteus

7. Magnetic Reed Switch Library for Proteus

A magnetic reed switch is a device used to identify the magnetic field and control electricity in the surroundings. They are composed of ferrous reeds encapsulated in a small glass that is sensitive to the magnetic field in the switch. It finds applications in electromagnetic projects and fluid-level sensors to measure motor oil.

We’re sharing this library first time as you won’t find it in the proteus database before. Click the link below to download a magnetic reed switch library for Proteus.

Download Magnetic Reed Switch Library for Proteus

8. Infrared Sensor Library for Proteus

Infrared sensors are used for obstacle detection. They use infrared rays to identify if there is any obstacle in front. These sensors come in two parts: one is a transmitter that transmits the infrared rays and the other is the receiver that receives these rays after getting reflected from the object. They are also used to detect the heat emitted by an object. Infrared sensors find applications in robotics and automation for security purposes. The Proteus library zip file download link is as follows:

Download Infrared Sensor Library for Proteus

That was all about New Proteus Libraries of Digital Sensors. I hope you like this article. I’ve dissected every piece in an easy-to-read and easy-to-understand step-by-step tutorial. You can DIY, simulate, and incorporate this library into your project just by reading our posts. If you find any difficulty in the simulation or execution of your proteus project, I’m here to help you. And don’t forget to share your valuable suggestions or feedback, they help us create quality content. Thank you for reading this post.

Proteus Libraries of Embedded Sensors

Hi Folks! Glad to see you here. Thank you for viewing this read. In this post today, I’m going to list New Proteus Libraries of Embedded Sensors.

I’ve shared scores of Proteus libraries and today I’m going to pack them into one single post that will help you scan through all libraries related to sensors in one place. Moreover, if you are alien to Proteus, you can check this post on how to add a new library in Proteus. I’m going to embed the link to each Proteus library added recently. You can download and simulate Proteus libraries from the respective links. Plus, all these libraries are compatible with Microcontrollers and Arduino boards.

All links you find in this post come with two simulations i.e. one simple simulation of the sensors and another simulation with the Arduino board. If you face any difficulty in simulating the library, you can pop your question in the section below, I’ll help you the best way I can. Before further ado, let’s jump right in and look at the list of New Proteus Libraries for Engineering Students. If your system doesn’t carry Proteus software already, you must have a look at How to Download and Install Proteus Software.

1. Ultrasonic Sensor Library for Proteus

Ultrasonic sensors are mainly used for obstacle detection. They use sound waves for object detection. Ultrasonic sound waves are emitted at a particular frequency which is then reflected back to the sensor after hitting the obstacle. The time these sound waves take in traveling from the sensors and then reflecting from the object is measured, which gives the total distance covered by the sound waves. It is important to note that these ultrasonic sound waves travel faster than the audible sound that we humans can hear.

We’ve designed an ultrasonic sensor library for proteus which you can easily run and simulate in proteus. The library is demonstrated with examples that will help you better understand these sensors covering three different scenarios. I’m sure you’ll love the working and simulation of this library that you can easily understand and incorporate into your semester project. The Proteus library zip file download link is as follows:

Download Ultrasonic Sensor Library for Proteus

2. PIR Sensor Library for Proteus

PIR (passive infrared) sensor is an electronic device that uses infrared rays for motion detection. They are based on thermal detection. They measure infrared rays reflected from objects that produce heat and thus infrared radiations in their field of view. Crystalline material incorporated at the center of the sensor detects infrared radiation. These sensors are mainly used for security purposes. You’ll find these sensors installed in bank security or home security systems.

We cannot measure real motion in proteus software unless we place TestPin. We don’t need this pin in real-time applications. We use this pin for proteus simulation only. When we give 5V to this pin, it will detect the motion and when zero voltage is applied, no motion is detected through this pin.

We’ve designed the proteus library of the PIR sensor, you can download the Library zip file from the link below:

Download PIR Sensor Library for Proteus

3. Gas Sensor Library for Proteus

A gas sensor is an electronic device mainly used to detect the presence of gases in the surrounding. Working is simple and straightforward. The gas sensor generates a potential difference based on the gas concentration in the atmosphere. This potential difference is directly related to the resistance of the inside material. This potential difference is measured as an output voltage that is directly proportional to the concentration of the gas.  The gas sensor is widely used in a variety of industries for the detection of gas leakage.

We’ve designed and added the library for the gas sensor which you can easily simulate in proteus. We’ve included the following 8 gas sensors in the library:

• MQ – 2
• MQ – 3
• MQ – 4
• MQ – 5
• MQ – 6
• MQ – 7
• MQ – 8
• MQ – 9

You can download the Gas sensor library for proteus by the link below.

Download Gas Sensor Library for Proteus

4. Flame Sensor Library for Proteus

A flame sensor is an electrical device mainly used to detect flame or fire. This sensor carries an infrared band that detects the presence of hot gases in the atmosphere. Installation of the flame sensor depends on the nature of work i.e. the presence of hot gases can lead to sounding the alarm, activation of the fire suspension system, or deactivation of fuel from the mainline. A flame sensor works better than a heat or smoke detector due to its quick response corresponding to hot gases. It is widely used in industrial furnaces, confirming if the furnace is running accurately.

Again, we cannot produce fire in the proteus software the reason we need to include the TestPin for the detection of fire. When the TestPin is HIGH it indicates the presence of flame and when it is LOW it projects the absence of flame.

We’ve designed and added Flame Sensor Library in Proteus, which you can download from the link below:

Download Flame Sensor Library for Proteus

5. Vibration Sensor Library for Proteus

A vibration sensor (also called a piezoelectric sensor) is an electrical device mainly used to detect vibration. It is a transducer that behaves like a switch to turn off or turn on the system when a certain vibration level is achieved. The vibration sensor might contain different sensitivity that depends on the nature of the application. Sensitivity is 500 mV/G for low-vibration applications and 100 mV/G for high-vibration applications.

These sensors are also used in security systems. If someone tries to break into your house, this sensor can detect the forced entry and produce a signal that triggers an alarm system.

Vibration plays a critical role in electrical and mechanical machines. These systems are configured with a specific number of vibration which if exceeds the recommended value, can damage the machine. These sensors confirm if machines are running with the required vibration.

Click the link below to download the vibration sensor library for the proteus.

Download Vibration Sensor Library for Proteus

6. Flex Sensor Library for Proteus

The flex sensor is also known as a bend sensor mainly used to measure the bending angle. The resistance of the sensor element is directly proportional to the value of the bend that the surface generates. The bend sensor is also called a flexible potentiometer. This sensor is widely used in security systems, rehabilitation research for measuring joint movement, and in computer and music interfaces. Dataglove is a common example of a flex sensor.

We’ve designed and added the library of this flex sensor in Proteus which you can download from the link below.

Download Flex Sensor Library for Proteus

7. Heart Beat Sensor Library for Proteus

A heartbeat sensor is used to detect the heartbeat of the human heart. It operates on the principle of light modulation. When a finger is placed on the sensor, it generates the digital output of the heartbeat. As you place the finger, it detects the blood flow that you can produce as a digital output on the LCD connected to Arduino Board or Microcontroller.

We’ve designed and added the library of this heartbeat sensor in Proteus. We’ve produced two versions of a heartbeat sensor where one version generates only one heartbeat pattern and the other produces multiple heartbeat patterns. The Proteus library zip file download link is as follows:

Download Heart Beat Sensor Library for Proteus

Download Heart Beat Sensor Library V2.0 for Proteus

8. Rain Sensor Library for Proteus

A rain sensor is a switching device used to detect rain. It finds applications in security systems and home automation. This sensor is also installed in some car windshields where it detects the presence of rainwater, giving an automatic signal to the windshield wipers that thus start cleaning the windshield. Rain sensor operates on the principle of total internal reflection with the use of infrared radiation. The infrared light beam is set at a 45-degree angle on the clear glass of the windshield. This sensor triggers when it starts raining. In the presence of rain, less amount of light is reflected back to the sensor. When this reflected light meets the preset value you already set earlier, it turns on the car wiper mechanism.

We’ve designed and added the library of rain sensors in Proteus which you can download from the link below.

Download Rain Sensor Library for Proteus

9. Soil Moisture Sensor Library for Proteus

Soil moisture sensor, as the name suggests, is used to measure the water content. It carries two probes where the resistance value of the current passing through the soil is used to record the moisture value. The probe is normally powered with a DC supply or batteries ranging from 3.3 to 20V that generates the output voltage ranging from 0 to 3V.

We’ve designed the library of soil moisture sensors in proteus. You won’t find this library before in the proteus library and we’re adding it the very first time. The Proteus library zip file download link is as follows:

Download Soil Moisture Sensor Library for Proteus

10. Water Sensor Library for Proteus

A water sensor is an electrical device used to detect the presence of water. It is mainly used for domestic and industrial purposes where it is used to detect water leakage. When it detects the leakage, it turns off the water supply to the house.

We’ve designed and added the library of water sensors in Proteus which you can download from the link below.

Download Water Sensor Library for Proteus

Conclusion

I've shared 10 New Proteus Libraries above for Engineering Students. Hope you find this post helpful. You can use these libraries in your semester project or anyway as you like better. Both simple sensor simulation and simulation with the Arduino board are added to the proteus library. And TestPin included in the sensor is only used for simulation purposes. You won't find this pin in the actual sensor.

Don’t forget to leave your comment in case you need my help. We keep sharing and adding new libraries on and off, not available in the proteus already. Feel free to leave your valuable suggestions about the libraries you think are not included in the Proteus library. We’ll try our best to include them from the get-go in easy-to-read and easy-to-understand tutorials. Thank you for reading this post.

Introduction to BC640

Hello Everyone! Hope you’re well today. Thank you for viewing this read. In this post today, I’ll be discussing the Introduction to BC640. BC640 is a bipolar junction transistor that belongs to the PNP transistor family. It is composed of silicon material and comes in a TO-92 package. It is used to drive load under 500mA. In this post, you’ll get to know everything related to BC640 covering pinout, working, alternatives, applications, and physical dimensions. Keep reading.

Introduction to BC640

• BC640 is a PNP bipolar junction transistor mainly used for amplification and switching purpose.
• It comes with three pins called the emitter, base, and collector.
• The base is the main terminal responsible for the entire transistor reaction. The small current change at the base terminal is used to control large current across remaining terminals. The reason, it’s also called current controlled device in contrast to FET (field-effect transistors) which is a voltage-controlled device.
• BC640 carries three layers where one n-doped layer is placed between two p-doped layers.
• As this is a PNP transistor, here current flows from emitter to collector as opposed to NPN transistor where current flows from collector to emitter.

• Both holes and electrons play a critical role in conductivity. In the case of PNP transistors, holes are the majority carriers and electrons are major charge carriers in NPN transistors.
• It is important to note that NPN transistors are preferred over PNP transistors because the movement of electron is better and faster than the movement of holes. In some electronic projects, both PNP and its complementary NPN are combined and incorporated into a single circuit.

• When two diodes are joined together from the cathode side, they produce PNP transistors. Here N-layer represents the base terminal while remaining layers represents emitter and collector respectively.

• In PNP transistor there is no current at the base side when the transistor is turned ON, while in NPN transistor electrons start flowing through the base terminal when the bias voltage is applied.

 

Where To Buy?
No.	Components	Distributor	Link To Buy
1	BC640	Amazon	Buy Now

BC640 Datasheet

• It’s always better to sift through the datasheet and get a hold of the main features of the component.
• Download BC640 datasheet by clicking the button given below:

Download BC640 Datasheet

BC640 Pinout

BC640 carries three pins named: 1: Emitter 2: Base 3: Collector The following figure shows the pinout of BC640.

• All these pins are used for the external connection with the electronic circuits, and they all are different in terms of their functions and doping concentrations.
• The doping concentration in the emitter terminal is higher than both base and collector terminals.

BC640 Working Principle

• Both PNP and NPN transistors almost work similarly with some exceptions.
• The voltage polarities and current directions in PNP transistors appear opposite compared to NPN transistors.
• The base is still considered the main area responsible for the overall transistor action.

• As holes are majority carriers in this PNP transistor, now holes are emitted from the emitter terminal (electrons are emitted from the emitter in case of NPN transistor) which are then collected by the collector.
• It is important to note that when there is no current present at the base terminal, PNP transistor is turned ON and when current flows through the base it is considered turned OFF.

BC640 Power Ratings

The following image shows the absolute maximum ratings of BC640.

Absolute Maximum Ratings BC639
No.	Rating	Symbol	Value	Unit
1	Collector-Emitter Voltage	Vce	80	V
2	Collector-Base Voltage	Vcb	80	V
3	Emitter-Base Voltage	Veb	5	V
4	Collector Current	Ic	500	mA
5	Total Device Dissipation	Pd	625	mW
6	Transition Frequency	ft	50	MHz
7	Storage Temperature	Tstg	-55 to 150	C

• Both collector-emitter and collector-base voltages are 80V while the emitter-base voltage is only 5V which means the only 5V is required to trigger the transistor reaction.
• Device dissipation is 625mW which implies the amount of heat it produces as a byproduct due to its primary action.
• Collector current is 500mA which projects the value of load it can drive. The transition frequency is 50MHz which is a measure of the high-frequency operating characteristics of a transistor.
• These are the stress ratings. Make sure these ratings don’t surpass the absolute maximum ratings, else they will damage the component, thus the entire project.
• Moreover, extended exposure to stresses above recommended absolute maximum ratings can influence the device reliability.

Difference between PNP and NPN transistors

• Current direction is the major difference in both NPN and PNP transistors.
• Recall, current flows from emitter to collector in PNP transistor when a negative voltage is applied to the base terminal and current flows from collector to emitter in NPN transistor when a positive voltage is applied at the base terminal.
• In both cases, the base terminal is responsible for the electron reaction.
• In NPN transistor, the transistor turns on when current flows through the base terminal, and in case of PNP transistor, the device turns on when there is no current at the base terminal.

• Both transistors are the primary components used in modern electronic projects.
• It is important to note that both NPN and PNP transistors are interchangeable and are made up of two back to back diodes where one is forward biased and the other is reverse biased.
• The main difference stands in the polarities of the applied voltage at the base terminal and current direction as mentioned above.

• In conclusion, both PNP and NPN are interchangeable and work perfectly well if we change the polarity of the applied voltage.

BC640 Alternatives

Following are BC640 alternatives:

• BC618
• BC635
• BC636
• BC637

Better check the pinout of the alternatives before embedding them into your projects, as it’s likely they might carry different pinout than BC640. The complementary NPN transistor to the BC640 is BC639.

BC640 Applications

The following are some applications of the BC640.

• It is used to source current, i.e. current flows out of the collector.
• Used for switching and amplification purpose.
• Used in electronic motors to control current.
• Employed in the push button.
• Used in robotics and instrumentation.
• Finds applications in Darlington pair circuits.

BC640 Physical dimensions

The following figure shows the physical dimensions of the BC640. That’s all for today. I hope you’ve got an insight into the Introduction to BC640. If you have any question, you can approach me in the comment section below, I’d love to help you the best way I can. You’re most welcome to share your feedback and suggestions, they help us provide quality work. Thank you for reading this post.

Water Sensor Library For Proteus

Hello Everyone! Happy to see you here. I welcome you on board. In this tutorial, I’ll walk you through the Water Sensor Library for Proteus. You won't find this library in the proteus software, and we are introducing it for the very first time. It will help you to better understand the working/ operation of the water sensor.

If you want a proteus library of any sensor, that is not available in proteus already, you can share it in the comments below, I’ll try my best to create and share that library asap.

Before I go further, it’s better to scratch and get a hold of what is a water sensor? A water sensor is an electronic sensor, used to detect the presence of water. It detects the water by measuring the water's electrical conductivity. These sensors are mainly used to ward off the flow of water in case any leakage happens. This device is mainly used for detecting water levels, rainfall, and water leakage.

Let’s dive in and study how to download and simulate Water Sensor Library For Proteus.

Water Sensor Library For Proteus

• Click the button below, to download a water sensor library for proteus:

Water Sensor Library For Proteus

• As you download the file, it will appear in a .zip file that comes with two folders named: Proteus Library and Proteus Simulation.

Now, you have to open the proteus library folder that carries three files, named:

• WaterSensorTEP.IDX
• WaterSensorTEP.LIB
• WaterSensorTEP.HEX

• Copy all these three files and paste them into the Library Folder of the Proteus software.

• After doing this drill, you have to start the proteus software. If it’s already open, restart.
• After starting the proteus software, search for the water sensor available in the component’s search box as mentioned below:

• As you search for the sensor, you will get the figure below. This is our water sensor library for proteus that we have recently added to the proteus library.

• As you click ‘OK’ you’ll watch the sensor appearing as a blinking image, indicating you can place this sensor anywhere you want in the proteus workspace. After doing this, you’ll get the below result:

• Almost half work is done. You’ve created the proteus workspace with the water sensor.

Sensor Layout

Still reading? Perfect. Before I move further and discuss how to add a sensor’s hex file and run a proteus simulation of the water sensor, let’s discuss the sensor’s pins and layout first. This water sensor comes with four pins as follows:

• (S): This is an analog output pin that is used for the connection with the input of the circuit.
• (-): This pin is connected to the ground.
• (+): This is a power supply pin that is used to power the sensor. It is officially recommended to connect this pin with a voltage ranging from 3.3V to 5V.
• TestPin: This test pin is used for proteus simulation. You won’t find this pin in real-time on the water sensor.

The sensor comes with ten exposed copper traces where five are sense trances and the remaining are power traces.

• Though these copper trances are not directly connected, they stand connected when they all are submerged in water. Generally, they are placed together where one sense trace stands between two power traces.
• There is one LED incorporated on the board that turns on when the sensor is powered.

Working Of Water Sensor

Working is pretty simple.

• The exposed parallel traces work as a variable resistor whose resistance is directly related to the water level.
• The sensor resistance is inversely proportional to the water level.
• When the sensor is fully immersed it shows the low resistance, thus indicating more height of the water.

• And when the sensor is partially immersed, it shows more resistance, and less conductivity, thus indicating less height in correspondence with the resistance.
• This variable resistance is directly related to the voltage appearing across the sensor. By measuring that voltage we can detect the water level.

Adding Sensor’s Hex File

• I hope you’ve got a clear idea of how this sensor works and detects the water level. Now, we’ll add the hex file of this sensor available in the library folder.

You can do it in two ways.

• Right-click on the water sensor and look for “Edit Properties” as shown in the figure below.

• You can also get the “Edit Properties” panel by double-clicking on the sensor.
• Now, you can add the sensor’s hex file by clicking the browse button as shown below. This file you can find in the library folder of the proteus software.

• You’ve added the hex file successfully. Now click “OK” and close the “Edit Properties” panel.

Proteus Simulation of Water Sensor

• Now we simulate the sensor we’ve produced in the proteus workspace.
• To do this, we’ll design a small LC circuit that will help simulate the water sensor.
• Connecting the LC circuit with the sensor is simple and straightforward. We’ll connect the sensor’s analog output pin (S) with the LC circuit through a voltmeter. And we’ll attach the variable resistor to the TestPin of the sensor. This resistance of this variable resistor will help us detect the water.
• The voltage on this voltmeter connected with the LC circuit gives the value against the variable resistor.

• When the resistance is zero, it gives the maximum voltage across the voltmeter i.e. 4.97V. Recall, when the sensor is fully immersed in water, it shows zero resistance, thus indicating more height of the water level.
• And when we start increasing the resistance across the variable resistor, the voltage on the voltmeter will start decreasing, thus indicating the sensor is not immersed in water, projecting the low height of the water level.
• There is a reason we’ve connected the sensor with the LC circuit. Because proteus always provides the peak-to-peak value of the sensor and we need to convert that peak-to-peak value into Vrms.
• We are using this LC circuit to run our proteus simulation, we don’t need it in the real-time hardware implementation of the water sensor.

• We’ve done it. This is the complete simulation of the water sensor. This water sensor library is not available in the Proteus library, we’ve added it the very first time.
• Now, click the play button at the bottom left of Proteus software, it will show the result above.

Water Sensor with Arduino

• Now, we’ll attach this sensor with Arduino.
• We’ll connect the output of the water sensor appearing across the voltmeter to the analog input pin of the Arduino board.

• When the resistance is zero, the voltage will appear as 4.97V, thus giving an equivalent analog value of 1019 on the LCD attached to the Arduino Board.

That’s all for today. Hope you’ve got a clear insight into how to simulate a water sensor library for proteus. If you have any questions, you are most welcome to ask me in the comment section below, I’ll try my best to help you according to the best of my expertise. In the upcoming tutorials, I’ll keep adding more libraries in proteus around sensors and others not available in the library, already. Thank you for your precious time. Stay tuned!

Soil Moisture Sensor Library For Proteus

Update: We have created a new version of this library, which you can check here: Soil Moisture Sensor Library for Proteus V2.0.

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Hi Friends! Hope you’re well today. I welcome you on board. In this tutorial, I’ll be discussing the Soil Moisture Sensor Library for Proteus. You won't find Soil Moisture Sensor Library in Proteus and we’re going to share its Proteus Library very first time. I have previously shared many Proteus Libraries for digital and analog sensors and today I’m discussing something new. Excited to get a hold of the Soil Moisture Sensor Library? Me too. In the upcoming days, I’ll keep sharing different libraries related to sensors. If you’re curious to sneak into the nitty-gritty of sensors not available in the Proteus library already, pop your suggestion in the comment section below. I’ll try my best to comply with your suggestions and walk you through something brand new.

Soil moisture sensors are used to measure the water content in the soil. They use capacitance to measure the dielectric permittivity of the soil which defines the function of the water content. Before further ado, let’s dive in and have a look at How to download and simulate Soil Moisture Sensor Library for Proteus:

Where To Buy?
No.	Components	Distributor	Link To Buy
1	LCD 20x4	Amazon	Buy Now
2	Arduino Uno	Amazon	Buy Now

Soil Moisture Sensor Library For Proteus

• You can download the Proteus Library zip file of Soil Moisture Sensor Library by clicking the button below.

Download Proteus Library Files

• It’s a .zip file that contains two folders inside i.e. Proteus Library & Proteus Simulations.
• The real fun starts right here right away.
• Open proteus library folder that contains three files named:
  • SoilMoistureSensorTEP.IDX
  • SoilMoistureSensorTEP.LIB
  • SoilMoistureSensorTEP.HEX
• Copy and paste these three files in the Library folder of your Proteus software:

• Now, we need to run the Proteus ISIS software and don't forget to restart, if it's already open.
• Look for the Soil Moisture in the component’s search box as shown below.

• After installing the Library successfully, you’ll get similar results as below:

• You can see in the figure above we have one Soil Moisture Sensor.
• Now simply place this Soil Moisture Sensor in your Proteus workspace, as mentioned below:

• You can see in the figure above, I have placed one Soil Moisture Sensor inside the Proteus workspace.
• This sensor carries 4 pins in total, named:

• V (Vcc): We’ll provide +5V here.
• G (GND): We’ll provide ground here.
• Ao (Out): It’s an analog output signal from the sensor.
• TestPin: It is used for simulation purposes only. Soil Moisture Sensor doesn’t contain this pin in real.

Adding Sensor’s Hex File

• After this drill, we’ll add the Sensor’s Hex File, which we have downloaded and placed in the Library folder.
• To do that, right-click on your Soil Moisture Sensor and then click on “Edit Properties” as below:

• Or you can double click the Soil Moisture Sensor, it will pop the window below:

• Click on the Browse button and add SoilMoistureSensorTEP.HEX file available in the Proteus Library section as shown in the figure below:

• After adding the Sensor’s Hex File, click on the ‘OK’ button to close the ‘Edit Properties’ Panel.
• Our Soil Moisture Sensor is now ready to simulate in our Proteus ISIS.
• We’ll design a small circuit to thoroughly understand the working of this Soil Moisture Sensor.

Proteus Simulation of Soil Moisture Sensor

• Here, I’m designing a simple circuit. I’ve attached a variable resistor with the Test Pin & added a Voltmeter at the Output pin, as shown in the figure below:

• This resister defines the soil water content in the proteus simulation.
• When the resistance is maximum at the test pin, the circuit shows zero volts across the voltmeter, which means the sensor is either in the dry ground or taken out of the ground i.e. giving zero moisture value of the water content.
• And when resistance is zero, the circuit will show the maximum voltage across the voltmeter which indicates the sensor is inserted in a wet ground i.e. water contents in the soil are too high.
• This is important. We have attached the output pin with an LC filter. This filter is not required in real hardware implementation.
• We are using it in Proteus Simulation only as Proteus gives the peak-to-peak value and we have to convert that PP value into Vrms.
• If you are working on a real sensor then you don’t need to add this LC circuit.
• Now, let’s run this Proteus Simulation and if you have done everything as mentioned, it will show the result mentioned in the figure above.

Simulation of Soil Moisture Sensor with Arduino

Now, let's interface this sensor with a microcontroller.

• We have attached the output of the sensor appearing across the voltmeter with the A0 pin of the microcontroller as below.

You can see we get the analog value 1019 when the voltage across the voltmeter is 4.98V

This is it. I hope you find this tutorial helpful. This will help engineering students in simulating their semester projects in proteus. In the next tutorials, I’ll be sharing and adding more libraries of sensors. You’re most welcome to share your suggestions with the sensors you want me to libraries of. If you’re unsure or have any questions, you can ask me in the section below. I’ll help the best way I can. Thank you for reading this article.

Introduction to BC327

Hi Friends! Glad to see you here. I welcome you on board. In this post today, I’ll be discussing the Introduction to BC327. BC327 is a bipolar junction transistor that falls under the family of PNP transistors. It is composed of silicone material and is used to drive load under 800mA. It’s a current-controlled device that carries three pins where small current generated at the one terminal is used to control large current at the other terminals. Read this post all the way through as you’ll get to know all nuts and bolts of BC327 covering pinout, working, power ratings, applications, and physical dimensions. Let’s get started.

Where To Buy?
No.	Components	Distributor	Link To Buy
1	BC327	Amazon	Buy Now

Introduction to BC327

• BC327 is a PNP bipolar junction transistor that comes in the TO-92 package and is used for switching and amplification purpose.
• It comes with three pins named emitter, base, and collector that are mainly used for external connection with the electronic circuit.
• BC327 is incorporated with three layers where one n-doped layer is sandwiched between two p-doped layers. The n-doped layer is negative while the p-doped layer is positively charged.

• This transistor incorporates 800mA collector current, hence it is easily employed to drive a variety of heavy loads.

• Collector dissipation is 625mW while the maximum current gain is 630 which makes it a suitable pick for audio amplification purposes.
• Transistors are mainly divided into two types named NPN and PNP transistors this BC327 transistor belongs to the PNP transistor family.
• Both transistors are different in terms of their charge carriers used for conductivity.
• Electrons are major carriers in NPN transistors while holes are major carriers in PNP transistors.
• When two diodes are combined from the cathode side, they constitute a PNP transistor where the N-doped layer represents the base side while the other two p-doped layers represent the emitter and collector respectively.

• You know it already, the movement of electrons is far better and faster than the movement of holes. The reason NPN transistors have a leg over PNP transistors for their quick response in conductivity.

BC327 Datasheet

• To understand the component thoroughly, it’s always wise to sift through the datasheet.
• Download BC327 Datasheet by clicking the button below:

BC327 Pinout

BC327 comes with three pins named 1: Emitter 2: Base 3: Collector The following figure shows the pinout of BC327.

• These pins are used for external connection with the electronic circuit. The small current change at the base terminal produces a large current change across other terminals.
• The base terminal plays a key role in differentiating both NPN and PNP transistors.
• In NPN transistor current flows through the base side when voltage is applied while in PNP transistor no current flows through the base terminal when the transistor is turned ON.

BC327 Working Principle

• When current flows through the base terminal in this PNP transistor, the transistor is turned OFF, and on the other hand, when there is no current at the base side, the transistor is turned ON.
• PNP works the same as NPN transistor but in the opposite fashion. The base still controls the large current across other terminal but here current flows in the opposite direction i.e. from emitter to collector.
• And instead of electrons emitted in the case of NPN transistor, holes are emitted by the emitter in PNP transistor that are then collected by the collector.

BC327 Power Ratings

The following table shows the absolute maximum ratings of BC327.

Absolute Maximum Ratings BC639
No.	Rating	Symbol	Value	Unit
1	Collector-Emitter Voltage	Vce	45	V
2	Collector-Base Voltage	Vcb	50	V
3	Emitter-Base Voltage	Veb	5	V
4	Collector Current	Ic	800	mA
5	Collector Power Dissipation	Pc	625	mW
6	Junction Temperature	Tj	150	ºC
7	Storage Temperature	Tstg	-55 to 150	ºC

• These are stress ratings that can make or break your entire project. Make sure ratings don’t exceed these absolute maximum ratings else you may compromise your component.
• Similarly, if these ratings are applied for more than the required time, they can affect the reliability of the device.

Difference between PNP and NPN Transistors

• The BC327 transistor carriers the same characteristics as NPN transistors with a few exceptions.
• In the case of PNP transistors, all current directions and voltage polarities will be reversed compared to NPN transistors.
• The NPN transistor sources current through the base terminal while PNP sinks current into the base terminal, the reason it’s also called a sinking device.
• In PNP transistor the base terminal is more negative than the emitter terminal. And all these terminals are different in terms of their doping concentration.
• The emitter terminal is highly doped and comes with 100% current of the transistor while the base terminal is lightly doped and is responsible for the transistor action and controls the number of holes emitter from the emitter which are then collected by the collector.

• The collector terminal is bigger compared to other terminal and is lightly doped.
• Both NPN and PNP also differ with respect to the applied source voltage i.e. in case of NPN transistor source voltage is applied at the collector side while in case of PNP transistor source voltage is applied at the emitter side.
• A load resistor is also used while working with this BC327 PNP transistor that controls the current in the collector terminal.
• Plus, biased voltage is applied at the base terminal that initiates the transistor action and it is coupled with the base resistor to resist and limit the current flowing through this terminal.

BC327 Alternatives

The following are alternatives to BC327.

• 2N4403
• BC488
• BC638
• 2N4402
• 2N3702
• 2N3703
• BC486
• BC490
• BC328

The pinout settings of the alternative may differ from the actual BC327. It’s wise to check the pinout of the transistor before employing it in your electronic circuit. NPN Complementary of BC327 is BC337. Since they both form a complementary pair, they can be employed together in many electronic projects.

BC327 Applications

BC327 comes with the following applications:

• Used for signal amplification and switching purposes.
• Finds application microcontrollers to drive heavy loads.
• Used in audio amplifiers and multiple preamplification stages.
• Employed to drive loads under 800mA.
• Used in push-pull configuration circuits.
• Used in medium-speed switching and high-frequency amplifiers.

BC327 Physical dimensions

The following figure shows the physical dimensions of the BC327. That’s all for today. I hope you find this read useful. If you have any questions, you can approach me in the section below. I’d love to help you the best way I can. Keep us updated with your valuable feedback and suggestions, they help us create quality content. Thank you for reading this post.

Introduction to BC550

Hi Guys! Happy to see you here. Thank you for viewing this read. In this post today, I’ll walk you through the complete Introduction to BC550. BC550 is a low-power low-frequency general-purpose bipolar transistor. It is mainly used to drive loads under 100mA. BC550 carries three terminals where a small current across one terminal is used to control the large current across the remaining terminals. It’s primarily used for amplification and switching purposes. Transistors are critical components and building blocks of modern electronic circuits. Bipolar junction transistors are divided into two main types named NPN transistors and PNP transistors. The BC550 falls under the category of NPN transistors and is available in a plastic TO-92 case. I suggest you read this entire post all the way through as you’ll get to know all nitty-gritty of BC550 i.e. datasheet, pinout, working principle, power ratings, applications, and physical dimensions.

Keep reading.

Where To Buy?
No.	Components	Distributor	Link To Buy
1	BC550	Amazon	Buy Now

Introduction to BC550

• BC550 is an NPN bipolar junction transistor mainly used for switching and amplification purpose.
• It incorporates three pins called the emitter, base, and collector. Where small current change at the base terminal is used to induce large current change across other terminals.
• BC550 carries three layers i.e. two N-doped layers and one P-doped layer. The P-doped layer indicates a positively charged layer that stands between the two N-doped layers that are negatively charged.
• When this transistor acts as a switch it is used to turn ON and OFF the input signal. When a powerful signal passes through the transistor, it turns ON the switch while lack of signal turns the switch OFF.
• When several thousands of millions of transistors are formed together, they can be incorporated into integrated circuits or in discrete components.
• BC550 is composed of semiconductor material. Silicon is mostly used to form these NPN transistors.
• In this NPN transistor, electrons are the majority carriers used for conductivity as opposed to PNP transistors where conductivity is carried out with holes as majority carriers.
• It is important to note that the movement of electrons is far better and faster than the movement of holes, the reason NPN transistors are better, thus preferred over PNP transistors.
• The main difference between NPN and PNP transistors is the behavior of the base terminal. In NPN transistors, current flows through the base terminal while in the case of PNP transistors no current flows through the base terminal when a transistor is ON.
• Also, the current flows from collector to emitter in NPN transistors, and in PNP transistors current flows from emitter to collector.
• Computer circuit boards are the common example of NPN transistors that carry millions of transistors used to store memory in the form of binary code.

BC550 Datasheet

• To understand the component thoroughly, it’s always wise to scan the datasheet.
• You can download BC550 Datasheet by clicking the button below:

BC550 Pinout

BC550 comes with three pins called

1. Emitter
2. Base
3. Collector

The following figure shows the pinout of the BC550:

• All these terminals are different in terms of their doping and functions.
• The emitter terminal is highly doped compared to the other two terminals.
• The emitter emits the electron into the base terminal which controls the number of electrons. The collector terminal is used to collect the number of electrons.

BC550 Pin Configuration

BC550 can be embedded in the following three configurations:

1. Common emitter configuration
2. Common collector configuration
3. Common base configuration

• Mostly amplification is carried out using a common emitter configuration as it comes with the exact voltage and current ratings required for amplification purposes.
• The amplification factor is an important factor used to define the nature of amplification. It’s a ratio between collector current and base current and is denoted by ß.
• The current gain is another factor which is a ratio between collector current and emitter current. It is denoted by a and is known as alpha. The alpha value ranges from 0.95 to 0.99 but mostly its value is taken as unity.

BC550 Working Principle

• In BC550, the base works as an electron valve that controls the number of electrons. When a voltage is applied across the base terminal, it triggers the electron reaction. Thus, the emitter starts emitting the electrons into the base terminal which are then collected by the collector.
• A small change in input voltage at the base terminal produces a large change in output voltage across other terminals. This phenomenon is used for amplification purposes.

• The collector voltage is always positive with respect to the emitter terminal while the base terminal is positive with respect to the emitter.
• And the collector terminal is combined with the load voltage using a resistor which is used to control the flow of current.

BC550 Power Ratings

The following table shows the absolute maximum ratings of BC550:

Absolute Maximum Ratings BC639
No.	Rating	Symbol	Value	Unit
1	Collector-Emitter Voltage	Vce	45	V
2	Collector-Base Voltage	Vcb	50	V
3	Emitter-Base Voltage	Veb	5	V
4	Collector Current	Ic	100	mA
5	Collector Power Dissipation	Pc	500	mW
6	Junction Temperature	Tj	150	ºC
7	Storage Temperature	Tstg	-55 to 150	ºC

• Emitter-Base voltage is 5V, which means the only 5V is required to trigger the base terminal, thus the entire transistor. While Collector-Base and Collector-Emitter voltages are 50V and 45V respectively.
• The collector current is 100mA i.e. it can drive loads with a value under 100mA.
• It’s wise to do your due diligence before incorporating this tiny device into your project as values exceeding absolute maximum ratings can severely damage the component.
• Plus, make sure you don’t apply these values for more than the required time, else they can affect the device's reliability.

BC550 Alternatives

BC550 equivalent are:

• BC546
• BC547
• BC548
• BC549

The complementary PNP transistor of the BC550 is BC560. BC550 Applications

• Used for amplification and switching purposes.
• Can be employed in the current mirror and H-bridge circuits.
• Used in linear amplifier and impedance buffering.
• Finds applications in oscillator and comparator circuits.
• Used in Astable and Bistable multivibrator circuits.
• Used for pre-amplification stages in electronic circuits.

BC550 Physical dimensions

The following figure shows the physical dimensions of the BC550: That’s all for today. Hope you’ve got a clear insight into the Introduction to BC550. You’re most welcome to ask your queries in the section below. I’d love to help you the best way I can. Feel free to keep us updated with your valuable suggestions and feedback. Thank you for reading this post.

Introduction to BC639

Hi Friends! Happy to see you here. I welcome you on board. In this post, I’ll walk you through the Introduction to BC639. BC639 is a high current gain bipolar junction transistor that falls under the NPN transistor family. It constitutes a high collector current and low collector-emitter saturation voltage and is widely used for amplification and switching purposes. It is used to drive load under 500mA. Collector Dissipation is 0.625W while DC Current Gain (hfe) ranges from - 40 to 160 with transition frequency 200MHz. In this post, I’m going to discuss all nitty-gritty of the BC639 transistor covering pinout, working, power ratings, alternatives, applications, and physical dimensions. Continue reading.

Introduction to BC639

• BC639 is an NPN bipolar junction transistor that carries high collector current and low collector-emitter saturation voltage.
• It is composed of silicon material and comes in a TO-92 package.
• BC639 carries three pins named emitter, base, and collector.

• It is mainly known as a current-controlled device where the base terminal is responsible for the entire transistor action.
• BC639 contains three layers where one p-doped layer sits between two n-doped layers.
• The small input current change at the base terminal is used to control large output current at the other two terminals.
• The base terminal controls the flow of electrons and acts as a control value. The emitter terminal emits the electron passing through the base terminal which are then collected by the collector terminal.
• Both electrons and holes play a critical role in conductivity carried out by these tiny components. In the case of NPN transistor electrons are the major charge carriers while in the case of PNP transistors holes are major carriers.
• The movement of electrons is faster and better than the movement of holes for conductivity. The reason these NPN transistors are preferred over PNP transistors for the making and execution of electronic projects.

Where To Buy?
No.	Components	Distributor	Link To Buy
1	BC639	Amazon	Buy Now

BC639 Datasheet

• It’s always wise to scan through the datasheet and get a hold of the main features of the component.
• Download BC639 datasheet by the link given below:

BC639 Pinout

BC639 comes with three pins called 1: Emitter 2: Base 3: Collector The following figure shows the pinout of BC639. Recall, BC639 is used to amplify the weak signal. As this is an NPN transistor, here current flows from collector to emitter as opposed to PNP transistor where current flows from emitter to collector. All these terminals are different in terms of their functions and doping concentrations. The emitter side is highly doped as opposed to the other two terminals. These pins are used for external connection with the electronic circuits.

BC639 Pin Configuration

BC639 transistor is employed in the following three main configurations:

• 1: Common emitter configuration
• 2: Common collector configuration
• 3: Common base configuration

• Common emitter configuration is used for the amplification purpose as it contains the suitable voltage and current ratings needed for amplification purposes.
• The nature of amplification is demonstrated by the amplification factor that is a ratio between collector current and base current. It is denoted by ß.
• The current gain is another important factor used to describe the nature transistor. It is a ratio between collector current and emitter current. It is called alpha and is denoted by a. The alpha value stands from 0.95 to 0.99 but frequently its value is taken as unity.

BC639 Working Principle

• It all starts from the base terminal. When the voltage is applied at the base pin, it ignites the electron reaction inside the transistor. This base pin controls the number of electrons emitted by the emitter terminal. The base pin acts as an electron valve and is responsible for conductivity inside the entire component.
• When BC639 acts as an amplifier, the small current at the base terminal (which acts as an input current) is used to control a much larger electric current at both emitter and collector terminals.
• And when it operates as a switch, it converts the small current at one part of the transistor into a much larger current across the remaining parts of the transistor.
• The base pin is positive with respect to the emitter terminal and collector voltage is always positive with respect to the emitter terminal.
• It’s important to note that the collector terminal is combined with the load voltage using resistor that limits and controls the flow of current.

BC639 Power Ratings

The following table shows the absolute maximum ratings of BC639.

Absolute Maximum Ratings BC639
No.	Rating	Symbol	Value	Unit
1	Collector-Emitter Voltage	Vce	60	V
2	Collector-Base Voltage	Vcb	60	V
3	Emitter-Base Voltage	Veb	5	V
4	Collector Current	Ic	500	mA
5	Current Gain	hfe	-40 to 160
6	Transition Frequency	ft	200	MHz
7	Storage Temperature	Tstg	-55 to 150	C

• Both collector-emitter and collector-base voltages are 60V while the emitter-base voltage is a mere 5V, which means the only 5V is required to trigger the electron reaction at the base terminal. And collector current is 500mA which projects that it can drive load under 500mA.
• The storage junction temperature range is -55 to 150C. While collector Dissipation is 0.625W and DC Current Gain (hfe) ranges from - 40 to 160 with transition frequency 200MHz.
• These are stress ratings that define the working of a component under certain values.
• If these values exceed the absolute maximum ratings, they can damage the component, thus the entire project.
• Do your due diligence before applying this component into your project and make sure you work under these mentioned ratings.
• Also, if these ratings are applied more than the required time, they can affect device reliability. Be careful.

BC639 Alternatives

KSC1009C transistor can be replaced by BC639. The complementary transistor of BC639 is BC640.

BC639 Applications

BC639 is used in the following applications:

• Used for amplification and switching purposes.
• Used in oscillator and comparator circuits.
• Employed in the current mirror and H-bridge circuits.
• Used for pre-amplification stages in electronic circuits.
• Finds applications in linear amplifier and impedance buffering.
• Incorporated in oscillator and comparator circuits.
• Used in Astable and Bistable multivibrator circuits.

BC639 Physical dimensions

The following figure shows the physical dimensions of the BC639. This is it. I hope you find this article helpful. I strive to share easy to read and easy to digest information. If you are unsure or have any question, you can pop a comment below, I’d love to help you the best way I can. Keep sharing your valuable feedback and suggestions, they help us create quality content. Thank you for your precious time.

Introduction to BC549

Hi Friends! I hope you’re well today. I welcome you on board. In this post, I’m going to discuss the Introduction to BC549. BC549 is a general purpose bipolar junction transistor that belongs to NPN transistor family. It contains three pins where small current change in one terminal produces a much large current change across other terminals. In other words, it is nothing but a current booster. It is known as a low power low voltage current controlled device and is used for switching and amplification purpose.  In this article I’ll be discussing complete details of BC549 transistor i.e. pinout, working principle, power ratings, physical dimensions and applications. Stay tuned.

Introduction to BC549

• BC549 is an NPN general-purpose bipolar junction transistor. It carries three pins named emitter, base, and collector and is available in TO-92 and SOT54 package.
• BC549 transistor contains three layers i.e. two N-doped layers and one P-doped layer. The P-doped layer stands between two N-doped layers. Plus, it contains two PN junctions where one is forward biased and the other is reverse biased.

• When no voltage is applied at the base terminal it is considered as grounded. In this case, the transistor acts like an open switch where both emitter and collector remain open.
• When voltage is applied at the base terminals it gets biased and draws current which is used to connect other terminals and current starts flowing from collector to emitter terminal.
• As this is an NPN transistor, here current flows from collector to emitter when voltage is applied, unlike PNP transistor where current flows from emitter to collector.
• Plus, both electrons and holes play a vital role in conductivity. In NPN transistor electrons are majority charge carriers and in PNP transistor holes are majority carriers.
• The movement of electrons, however, is faster than the movement of holes, the reason NPN transistors are better and faster than PNP transistors.

BC549 Pinout

BC549 comes with three pins named:

• 1: Emitter
• 2: Base
• 3: Collector

Following figure shows the pinout diagram of BC549.

• All three pins are used for external connections with other circuits. These pins are different in terms of operation and doping concentration.
• The collector voltage is larger than the base voltage and emitter terminal is highly doped compared to other terminals.

BC549 Pin Configuration

BC549 transistor can be employed in three main configurations as follows:

• Common emitter configuration
• Common base configuration
• Common collector configuration

Common emitter configuration is mostly used for amplification purposes as it contains the exact current and voltage ratings required for amplification.

• The amplification factor is called beta and is denoted by ß. It is mainly used to define the nature of amplification. It’s a ratio between collector current and base current. In BC549, the amplification factor ranges from 420 to 800.
• Another important factor is the current gain which is a ratio between collector current and emitter current. It is known as alpha and is denoted by a. The alpha value stands from 0.95 to 0.99 but more often than not its value is taken as unity.

BC549 Working Principle

• In BC549, emitter-base voltage is 5V which means when 5V is applied at the base terminal it gets biased and triggers the electron reaction.
• In the NPN transistor, the base terminal behaves like a control valve that controls the number of electrons.
• When voltage is applied at the base terminal, emitter starts emitting the electrons into the base terminal which controls the number of electrons. These emitted electrons passing through the base are collected by the collector terminal of the transistor.
• Moreover, the collector current is a mere 100mA i.e. you cannot drive heave loads using this transistor.
• As the only 5V is required to start the electron reaction at the base terminal, it can be easily employed across microcontrollers and microprocessors.
• When BC549 operates as an amplifier, small current as an input signal at the base terminal is used to induce a much bigger electric current at the other terminals.
• And when it works like a switch, it switches the small current at one part of the transistor into a much larger current across the other parts of the transistor.
• When transistor acts as a switch, it carriers two distinct states i.e. values are stored in the form of zero and one. Memory chip used in a computer is a common example of an electronic device that contains billions of transistors which can be turned on and off individually.

BC549 Power Ratings

Follow figure shows the absolute maximum rating of BC549:

• Emitter-Base voltage and Collector-Emitter voltages are 5V and 30V respectively.
• And Collector-Base voltage is 30V with collector current 100mA i.e. it cannot drive loads carrying ratings more than 100mA.
• The current gain ranges from 420 to 800 and transition frequency is 100MHz.
• These are stress ratings. Before you employ this transistor into your project and execute, make sure the ratings don’t exceed from absolute maximum ratings, else they will damage the product, and worse, your entire project, eventually.
• Also, if these ratings are applied for more than the required time, they can affect device reliability.

BC549 Alternatives

The following are the alternatives of a BC549 transistor.

• BC547
• BC548
• BC550

The PNP complementary of BC549 are:

• BC559
• BC560

BC549 Applications

BC549 can be used in the following applications:

• Used in liner audio amplifiers.
• Employed in Darlington pairs and sensor circuits.
• Used in oscillator and comparator circuits.
• Finds application in current mirror circuits.
• Used in Astable and Bistable multivibrators.
• Used for impedance buffering and switching applications.
• Finds application in low noise stages in audio frequency equipment.

BC549 Physical dimensions

Follow figure shows the physical dimensions of BC549: That’s all for today. Hope you find this article helpful. If you are unsure or have any question, you can approach me in the section below. I’d love to help you the best way I can. You’re most welcome to keep us updated with your valuable feedback and suggestions, they help us produce quality content. Thank you for reading this article.