[SOLVED] Which of these cell phone detectors have high sensitivity?

[Audioguru]

I'm starting to think the 1st video is fake.

The video was made in Pakistan which is a neighbour of India. People in India make millions of You Tube electronics videos to get paid by You Tube for each view of the ads. Many people posting the videos have poor knowledge of electronics.

 

[betwixt]

What are you trying to prove?
Everything you have shown so far is a simple loop, rectifier and LED. Given sufficient power it will light up the LED but so will a watch battery, a solar panel or a 'wall wart' PSU. I can't see any practical application for a design to light an LED dimly during a phone call when most phones have built in LEDs already.

And certainly DO NOT TRUST YOUTUBE VIDEOs, especially ones with electronic jingles in the background and a glue gun to hold wiring together. There are many and they are all fake or designed to mislead. As Audioguro points out, they are not educational, they exist only to make money for the uploader. There is even one on Youtube showing how to make free electricity by gluing engine spark plugs to the back of a loudspeaker!

Brian.

 

[unbuildpain]

What are you trying to prove?
Everything you have shown so far is a simple loop, rectifier and LED. Given sufficient power it will light up the LED but so will a watch battery, a solar panel or a 'wall wart' PSU. I can't see any practical application for a design to light an LED dimly during a phone call when most phones have built in LEDs already.

And certainly DO NOT TRUST YOUTUBE VIDEOs, especially ones with electronic jingles in the background and a glue gun to hold wiring together. There are many and they are all fake or designed to mislead. As Audioguro points out, they are not educational, they exist only to make money for the uploader. There is even one on Youtube showing how to make free electricity by gluing engine spark plugs to the back of a loudspeaker!

Brian.

I'm doing this out of curiosity, to familiarize myself with how things work so that later on I can build things which I think will be useful to me.

The difference between battery, solar panel, etc is they have to be connected with wires, whereas this doesn't seem to require any power source, almost like magic to people who don't know about electronics.

 

[betwixt]

There is no magic I'm afraid.
What you are seeing is simply electromagnetic coupling between a source (the phone) and destination (the LED). It is much the same way as a power transformer works, a primary winding converts electrical current to a magnetic field and a secondary winding converts it back again without electrical contact between them. At much higher frequencies the same principle applies but the body of the transformer isn't needed and the number of turns on the secondary reduces to just one. Your components are making a loop which picks up some of the radiated signal and converts it back to the voltage that drives the LED.
What you are producing is extremely inefficient, consider you start with a powerful battery that could power a searchlight and end up with a dimly lit up LED!
If you wish to continue with your experiments, it will work better with a single diode, you need one but adding more just increases the losses. It is the length of the wiring in the loop that makes most difference to the output. You will probably find that a single diode wired across the LED works best.

Brian.

 

[unbuildpain]

It may not appear magical to you or me but to a layperson unaware of how electronics work, it could be passed off as magic.