Got few nano volt at metal roof of my house, can I use transformer to increase?

[Willen]

Few days ago I made a crystal radio. I used entire metal roof of my house as an antenna. Sound is better even in general earphone. So I guessed receiving power of my antenna is strong and collected more power with signals.

Then I connected a bright red LED between metal roof and earth, then the chip of red LED is glowing as a cat's eye. Can I use any simple small transformer to increase the volt to get little brighter LED?

 

[audioguru]

Your roof antenna picks up a certain amount of POWER. If you use a transformer to increase the voltage then for the power to remain the same the current must be decreased. Then the LED will not be brighter.

 

[unclejed613]

if you are able to light an LED with it, it's a lot more than a few nanovolts, as red LEDs begin conducting (and emitting) at about 1.4V

 

[ronsimpson]

When a cloud goes over head you will get more than nanovolts. I live where it is very dry and clouds build up millions of volts.

 

[MrAl]

Hi Willen,

You might have to investigate how this power is being generated. There are a number of natural physical processes that generate small amounts of power. We dont usually notice them until we see something on a larger scale happening, like rust. And in the past we didnt have much that could run on such small amounts of power, but now we have super bright LEDs that can light up even with tiny currents like 10ua.
It could be that if you put a lead from the four corners of the roof that you can light up 4 LEDs instead of just one for example. You can also try in series because at low current levels there might be enough voltage.

 

[Willen]

if you are able to light an LED with it, it's a lot more than a few nanovolts, as red LEDs begin conducting (and emitting) at about 1.4V

But I tried to measure the volt on digital MM it was very tiny so reading was around 0.001mV but reading was very unstable. I picked up the LED from optical mouse which has transparent package and gives bright red light.

I think 'MrAl' is saying right-

...but now we have super bright LEDs that can light up even with tiny currents like 10ua.

My LED is lighting up with VERY small light. Almost it is not emitting light but its chip is glowing.

 

[tcmtech]

You may very well be seeing the effects of your metal roof working like a large plate capacitor with it as one side and the earth ground as the other.

The weak current you are seeing may very well be AC and it's source is more from the ground than from the air.

A very sensitive oscilloscope could give you a visual view of the actual power and what frequency/frequencies it's at.

 

[ronsimpson]

Your metal roof might be connected to ground with a ground rod and you are seeing the voltage across the ground wire.

Some metal roofs are protected by a layer of paint. It will be hard to make a good connection. What is the resistance from one piece of roof to another a meter away? I can not get a resistance reading on a piece of roofing I have because of a coating on the metal.

 

[JimB]

Willen, have a look at this thread:

https://www.electro-tech-online.com...ure-from-a-simple-antenna.130178/#post1080176

To get an idea of what may be coming from your "roof antenna"

JimB

 

[Norator]

Your roof must be in a strong RF field or it is picking up current from the house wiring. Above 2 volts/meter or above 10 mA into a 300 or 3000 ohm resistor may be dangerous to you.

 

[Willen]

Your metal roof might be connected to ground with a ground rod and you are seeing the voltage across the ground wire.Some metal roofs are protected by a layer of paint. It will be hard to make a good connection. What is the resistance from one piece of roof to another a meter away?

i made ground connection to metal roof and played a crystal radio across it and light up a led too (separatly). When I connected both- radio and LED, then LED will not glow. I tested continuity between plates and found that each plates of my house are connected electrically as a single plate. Plates has no paint.

Your roof must be in a strong RF field or it ispicking up current from the house wiring. Above 2 volts/meter or above 10 mA into a 300 or 3000 ohm resistor may be dangerous to you.

No strong RF field around me. I am almost far from crowd town. There are few FM stations 10 to 20 km far (few hundred watt stations) and a AM station is 20 km far from me. So I think it is general to receive such current on my LARGE metal roof. Sometime here is no electricity but signals strength on roof antenna is same, so it is not picking up current from home wiring. What you mean by dangerous?

Can you guess all power sources of my metal roof?

 

[ericgibbs]

hi.
Look at this link.
https://en.wikipedia.org/wiki/File:NearField-Earth-eField.png

Section and graph of Near Earth eField, this could be the source of your roof potential.

E

 

[audioguru]

Your cheap multimeter is designed to measure only low frequency AC from 50Hz or 60Hz mains.
It measures almost nothing (nanovolts) at radio frequencies.

 

[Willen]

Nice Pictures 'JimB'
Then may be also I am receiving other various high frequencies than short wave AM.

And dear 'ericgibbs', I am confused ! Little complicated and new thing for me. May I read it in simple language?

 

[JimB]

Then may be also I am receiving other various high frequencies than short wave AM.

Your roof is a conductor, so, if any electromagnetic waves of whatever frequency pass by, they will induce a (small) voltage into your roof.

JimB

 

[Roff]

hi.
Look at this link.
https://en.wikipedia.org/wiki/File:NearField-Earth-eField.png

Section and graph of Near Earth eField, this could be the source of your roof potential.

E

**broken link removed** is an article on this subject.

 

[ChrisP58]

Regardless of where the power is coming from, it is a ridiculously small amount of energy. With the voltage in nanovolts, or even microvolts, even if you were somehow able to get an amp of current, you would still only have microwatts of power.

 

[Roff]

Regardless of where the power is coming from, it is a ridiculously small amount of energy. With the voltage in nanovolts, or even microvolts, even if you were somehow able to get an amp of current, you would still only have microwatts of power.

Agreed, but I think you have the voltage and current swapped. I think the voltage is relatively high, but the sustained current capability is miniscule.

 

[ChrisP58]

Agreed, but I think you have the voltage and current swapped. I think the voltage is relatively high, but the sustained current capability is miniscule.

I know that there is near zero current available. I was just pointing out that, based on Ohms law, even if you somehow could get current, that the OPs nanovolts would only produce nanowatts.

 

[Willen]

Here- **broken link removed** is an article on this subject.

I guessed sky voltage is produced by small small atmospheric particles instead of RF, am I right? Article is talking about thousands of volts, can I get high ampere with high voltage? (I think not) It is amazing!

I didn't think that we can also collect sky voltage through conductor. If this electrostatic charge can be collected, then can we collect static charges from out nylon clothes too?