Aerial (roof) rotating antenna operation?

The particular case here is one of those systems where you have a light antenna on the roof, a little box inside controlled by a remote control for rotating clockwise or counterclochwise and the antenna connection and box is through a single coaxial cable.

My questions are:
1) is the box sending a decodifiable signal through the coaxial cable or,
2) is it a wireless communication that exists between the box and the antenna motor?

In the case it's through the coaxial cable, if the controller box (the one at the living room) is damaged but the motor is working ok, how can I control the motor (forward/reverse) even if I've to use another pair of cables for the purpose?

Thanks in advanced for any help on this!

Power output from a mobile phone aux socket

Obviously it has a sufficient output to drive ear buds, but just how large a speaker would it drive? I like the idea of extension speakers but find the quality of bluetooth audio garbage so "hard wired" is the preferred option for me and if I can get away without a built in amp that would be great

Transistor Help

Hi guys,

I do not have a whole lot of knowledge concerning electronics so I am turning to the forums for information.
In my circuit I want to control a servo motor. But I only want to power this servo when I am using it.
Here comes the transistor in the picture. With a USB supplying 5V to the collector of the transistor, and a raspberry Pi supplying 2.5V to the Base. I thought the Emitter would pass through about 5V, but it is only passing 2V.

I need to power my server with roughly 5V and be able to control the power to this circuit with my Raspberry Pi.

Is this the right approach? What am I doing wrong

Thanks in advance for your help

Newbie Question: 12v led ?push button latching switch

I have a 12v led push button switch that I want to function like a regular push button that does not use any power, i.e. No led. I want to use the led, but when pushed I do not want to send power over the load, just close conductivity like a regular push button.

So, is there a way to drop the 12v that would normally be sent over the load to basically zero?

Thanks

How do constant current loads work and how to make one

Hi, I'm not the best at understanding electronics, how does a constant current load work and how can i make one, and what makes them have limits before they get fried?

Physical size of cap's

I have a cap on a board that is 405v 47uf 105'c and is 50mm long by 10mm (2" x 3/8").
Can I replace it with a cap of the same value but physically smaller ? Half the size.
It is in a switch mode psu.

window comparator help

I'm struggling on window comparator circuits.

I'm trying to build a game circuit that uses 6 wires. Each wire must go from point A to point B, C to D, E to F, ect. and only that wire can go in that relationship so if A to C nothing happens.

I thought a window comparator would have been the trick to make this work. using a voltage split and a lm324 but I can't get the lm324 to work properly. If anyone is interested I'm game for some assistance.

Phone Jack Types

Some of the schematics I am reading have two types of phone jacks, stereo and mono. the jacks are usually labled as Input and Output, and two out of three have the stereo jack on the input, and the mono jack on the output. I am really getting confused now, because I only have one of each for my project. the foxx diagram has the mono on the input, and the others have the stereo on the input. any good ideas on this? which way is best? most common? does it really matter?

Delay Switch Needed

hi, anyone have any idea if a circuit orproduct exists for the following:

I have a switch which I would like to have a delay of 30 minutes once my switch closes before completing the circuit. When my switch opens I would like to immediately open the circuit. I have 16 amps to control at 12v
Anyone able to help as imabit stumped?

Thanks

RS & Farnell codes

Hi

I have started a new supply business and normally get inquiries with Farnell codes. Is there a way to conver these into RS codes and find the exactly same item hoping the price will be cheap.

thanks
Syed Zain Nasir

I am Syed Zain Nasir, the founder of <a href=https://www.TheEngineeringProjects.com/>The Engineering Projects</a> (TEP). I am a programmer since 2009 before that I just search things, make small projects and now I am sharing my knowledge through this platform.I also work as a freelancer and did many projects related to programming and electrical circuitry. <a href=https://plus.google.com/+SyedZainNasir/>My Google Profile+</a>

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Syed Zain Nasir