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Found this site with crystal radio plans and came across these plans for a high power battery-less radios. In normal crystals the power rectified from the source transmitter is like a billionth of a watt and with a crystal headphone you can barely hear the 50000 watt news station across town. A lot of that has to do with the sensitivity of the human ear. These radios output enough power to drive a magnetic headset or so the literature linked here claims. Read the third sentance in the very first paragraph...
By using low powered transistors they switch an inductor..
Anyhow here is the link http://www.crystalradio.net/crystalp...ages/Free1.JPG which is a reprint from a 1960's era magazine article. on the last part of the address type free2 and so on to see the next page.
I also researched some patents by a gentleman by the name of Lloyd Crump that had a patent for a power supply tuned to radio waves not just from radio stations. His patents 2,813,242(figure 2) and 2,943,189(figure 3) are real interesting.
By using low powered transistors they switch an inductor..
Anyhow here is the link http://www.crystalradio.net/crystalp...ages/Free1.JPG which is a reprint from a 1960's era magazine article. on the last part of the address type free2 and so on to see the next page.
I also researched some patents by a gentleman by the name of Lloyd Crump that had a patent for a power supply tuned to radio waves not just from radio stations. His patents 2,813,242(figure 2) and 2,943,189(figure 3) are real interesting.
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