Lighting a LED with a candle flame

Jan Panteltje · 2012-10-01T10:18:18+00:00

Lighting a LED with a candle flame After reflecting on the circuit 'oscillator running on home made thermocouple', and failing to get a LED lighting up yesterday, it all fell into places, and I realized that the means to obtain the required 2V DC for the LED WASALREADY THERE. For the curious and experimenters, here is the complete diagram: Please, this is a BIG file, >3 MB And this is what the very simple circuit looks like: Scope is on source, to avoid loading. This home made thermocouple is really not suited for temperatures above 200 C, not only will the solder melt, but in the top of the candle flame it will simpleburn up (> 1000 C there). In the bottom of the candle flame you will be OK for a short while, better is to get perhaps a type E thermocouple, more voltage an it better standshigh temperatures. The LED is not very bright, and it is bright daylight here, perhaps tonight Iwill try to make a youtube video or better pictures with the LED visible. The secret to get the LED on, is in fact very simple. The waveform at the gates of the JFETs is limited by the gate source diodejunction conducting (max about 1.4 Vpp). So in fact there is already some gate current. Re-directing the gate current through the LED, and decoupling the LED, and moving it so it is ground connected, is all that is required. The voltage over the LED slowly rises as the gate current charges the 100 nFcapacitor, and at about 2 V all current goes into the LED, and it lights up.

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rickman 13 years ago

That is still not stealing. The power is being assertively transmitted into your space much like your neighbor watering his lawn and you catching the spray that falls on your lawn, or better, collecting the apples from his tree that fall on your side of the fence.

The FCC might be able to say you are disrupting his signal, but how easy would that be to prove in any meaningful way?

I meant power loss. If they are transmitting the power in the true sense of the term broadcast, then they would be hard pressed to claim you are stealing.

I read the other post about the long wire collector and I believe that poster affirms what I am saying. I wonder what is done about power lines that affect the transmission pattern of a radio station? Again, I think it would be a hugely hard case to assert even just regarding the interference.

I had an idea about a radio powered receiver. If there are close, strong transmitters in the area, that power could be captured to power receivers which could then receive other signals as well. I never followed up on this, but I've got nothing to do at the moment...

Rick

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Michael A. Terrell 13 years ago

Like I asked, have you ever performed field intensity tests at an AM radio transmitter site? A station I did some consulting work for had the land owner sell off part of the parcel to build a mall. The workers ripped up acres of copper wire grid when they paved the parking lot, which changed the radiation pattern. While they were working on that, the steel went up for the mall, and caused more problems. They had to end up adding another tower to keep from interfering with another station on that frequency.

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Michael A. Terrell 13 years ago

At what distance? Do it, and show the details. The field strength is measured in microvolts. How may miles of wire are you going to use? If the field strength was high enough "to extract hundreds of watts", you would have lethal levels of RF on the wiring and equipment in the transmitter building. At one 5 MW EIRP TV station, I couldn't pick up the station's output to feed an off air monitor in the control room. Luckily, Comark had provided a +10 dB test port for the test equipment.

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Michael A. Terrell 13 years ago

I worked at a radio & TV station at Ft. greely. The AM transmitter was a Gates BC250, 250 W at 790 KHz. It fed a center tapped dipole that later had the Alaskan power grid built on the same line 150 feet and directly above it. You could hear that station along the Alcan Highway all the way to Fairbanks, 105 miles away.

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Lund-Nielsen, Jorgen 13 years ago

Am 03.10.2012 23:46, schrieb Helmut Wabnig:

crude translation to english via Bing Babelfish:

Wireless lighting of the gazebos in the vicinity of radio station Billwerder Moorfleet is called hamburger light miracle, which took place shortly after its start-up. At that time, harnessed some allotmenters in this area long antenna wires and switched a light bulb that flashed through the energy trapped by the antenna between them and the ground. This power was revoked but the sender. As once the transmitter to maintenance was turned off, the engineers wondered that originated in the gazebos light and shone again at the restart of the transmitter. Because the use of transmitting energy for lighting purposes humbled the range of transmitter, a law was passed in a row which was the disruption of the operation of transmitters in Germany by the removal of the energy under penalty.

Jorgen

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