Lasersaber strikes again. A joule thief king ?

[Farmhand]

Nice work Tinsel, I noticed those little logic gates are very sensitive like that. It can be an interesting and a useful thing to be able to
detect signals and either collect them as Pirate said or amplify them. And the simpler the circuit the better.

Another part for the "Wanted" list.

Did anyone notice if Lasersaber ended up getting some dollars back on his prototypes ? I think a lot of us deserve to be able to
make some money back on working prototypes if we choose. Doing so might improve the build quality of some people like me as well.
Not that we all should go and buy 3D printers or anything.

..

P.S. If we sell a prototype we should include a schematic drawing on paper and a maybe a PDF or something with some information
and disclaimer with safety warning "if needed".

..

[Pirate88179]

This one is powered by the CR2032 or other 3v battery. The transistor is a very sensitive, high input impedance FET, a field effect transistor. The ambient electric field (DC from a charged piece of plastic, or AC from a Tesla coil or Slayer Exciter type circuit) is picked up (charges or discharges) by the Gate of the transistor which opens the channel from Drain to Source, lighting the LED with power from the battery. The field just switches the transistor, it doesn't power it.
So this is different from the electrosmog harvester, which is actually powered by resonating with the electromagnetic field of the smog source. The electrosmog harvester needs its power source to be AC RF at its resonant frequency. The Electrostatic Field detector  isn't powered by the field, and works best with a DC field produced by a static charge, either positive or negative, but it will respond to an AC field too but not as strongly.
It's a neat little circuit and should work with most any high-impedance FET. A CMOS logic gate can also be used but doesn't give the graded quasi-linear response to the field strength the way the FET does.
It's pretty  neat to be able to control the brightness of the LED by wiggling a piece of charged plastic a meter away. The charge can be from rubbing a comb thru your dry hair, or acrylic plastic against cloth, or the E field of a tesla coil, or etc.  The actuating charge builds up on the gate so this distance will change as the gate charge leaks onto or off of the gate. I tried a 10 meg resistor as pullup or pulldown for the gate, didn't work, must use at least 100 meg I guess.

Duh!  I saw the mention of the 2032 and skipped right over it.  Still, I think the idea of being able to run a single led from ambient energy (electrosmog) would be a worthwhile endeavor.  I have this ongoing argument with a buddy of mine who is an engineer. (electronics)  He claims that if I harvest energy from a local radio station (50,000 watts) it will cost them more money and they will have to up their output.  My argument is that that transmitter has no idea if one radio is tuned in, or 150,00 radios.  He says I am wrong.  He especially got mad when I asked if his engineering degree was mail order.  Go figure.

Bill

[SeaMonkey]

I have this ongoing argument with a buddy of mine who is an engineer. (electronics)  He claims that if I harvest energy from a local radio station (50,000 watts) it will cost them more money and they will have to up their output.  My argument is that that transmitter has no idea if one radio is tuned in, or 150,00 radios.  He says I am wrong.  He especially got mad when I asked if his engineering degree was mail order.  Go figure.

The Ground Wave Losses in AM Band propagation are
enormous within the several mile radius of the transmitting
antenna as losses within the soil and all metallic objects in
the signal path including the electrical grid.  Only about 50%
of the radiated energy from the antenna becomes sky-wave
or long range (more than ten miles) radiation.

Any energy your "harvester" may extract from the ground wave
would not even be noticed by the station. Even if you were able
to capture several hundred watts.

[magpwr]

The Ground Wave Losses in AM Band propagation are
enormous within the several mile radius of the transmitting
antenna as losses within the soil and all metallic objects in
the signal path including the electrical grid.  Only about 50%
of the radiated energy from the antenna becomes sky-wave
or long range (more than ten miles) radiation.

Any energy your "harvester" may extract from the ground wave
would not even be noticed by the station. Even if you were able
to capture several hundred watts.

hi SeaMonkey,

This is something interesting you mentioned about the power output of actual transmitting AM station.

I'm now curious what is the estimated electrical power usage in watt or kilowatt of a typical AM station transmitter.I have not started searching yet merely for knowledge purpose at this moment.

-----
Just found a very interesting less known facts about actual transmitter stations.
http://www.oldradio.com/current/bc_am.htm

quotes from site for ref-
In 2000, WHO, Des Moines, IA, with a 300 degree tall, sectionalized radiator has the highest reported efficiency of 471.54 mV/m/kW at 1 km. With it's 50 kW input, the radiated field is equivalent to 85 kW input to a "conforming" radiator.

A directional station, WWL, New Orleans generates a reported 3934.902 mV/m at 1 km

INTERNATIONALLY -  Continental Electronics has delivered AM transmitters at the 2 Megawatt level to the broadcasting organizations of several countries. It is reported that several fought a tendency for this level of RF power to melt and fuse the insulators and sand around the tower.

[SeaMonkey]

-----
Just found a very interesting less known facts about actual transmitter stations.
http://www.oldradio.com/current/bc_am.htm

quotes from site for ref-
In 2000, WHO, Des Moines, IA, with a 300 degree tall, sectionalized radiator has the highest reported efficiency of 471.54 mV/m/kW at 1 km. With it's 50 kW input, the radiated field is equivalent to 85 kW input to a "conforming" radiator.

A directional station, WWL, New Orleans generates a reported 3934.902 mV/m at 1 km

INTERNATIONALLY -  Continental Electronics has delivered AM transmitters at the 2 Megawatt level to the broadcasting organizations of several countries. It is reported that several fought a tendency for this level of RF power to melt and fuse the insulators and sand around the tower.

Very interesting finds.

The WHO tower in Des Moines (300 degrees tall) is nearly a full
wavelength which is designed to reduce the ground wave portion
of the radiated field and maximize the sky-wave portion of the
radiated field at a very low angle.  High technology at work.

The WWL New Orleans directional array is a group of towers
oriented to direct the bulk of the radiated energy to the North
thus producing a beam of very intense field strength.

Many of the AM Powerhouse stations of the 30s, 40s and 50s used
such directional arrays.

If they were designated "clear channel" they could maintain their
full power throughout the night time hours.  All other stations had
to reduce their power at sunset to 5 KiloWatts or less to minimize
long distance skip which could interfere with other distant stations
sharing the same frequency.  Some went to a night time power of
1000 watts or even less so were very hard for AM DXers to copy
at night in order to obtain a QSL Card.

Radio Programming back in those years (30s through 60s) was much
different than it is today.