From FB group Building Transistor Radios 2019-03-19 John Ferguson Yeah, I used to use the Sylvania ECG and the NTE catalogs to cross-reference transistors. But then I got some better product manuals from the makers, especially Motorola and National Semi. And I got hold of the professional industry documents. ECG and NTE give a ‘one
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from FB group Building Transistor Radios 2018 Dec 4 Terry Harris I didn’t try to mimic the ALD, I used the FETs for a voltage booster. The typical 5mm LED needs somewhere around 60 mW for Max brightness. If I was powering it with 60 millivolts, it would require over an amp to get the
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from FB group Building Transistor Radios 2018-11-19 Bob Johansen I worked at a company that had ESD mats on the workbenches, about 1980. We had wrist straps with a 1 Meg resistor in series with the cord to prevent shock hazard. I found that the leads of the resistors were broken but the heat shrink
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I watched this YouTube video where the author shows his FM transmitter using a big 60 volt power MOSFET. He also shows a very readable photo of the schematic. The video was made several years ago in 2012. He is powering this transmitter by connecting it to eleven 9 volt batteries in series, totalling 99
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I went online a few days ago and looked for some odd RF transistors, but instead I was shocked. Almost all of the parts I’ve been using are through hole parts, like transistors in a TO-92 package with wire leads. I looked at a few distributors such as Mouser, Avnet, Arrow, Digikey, Newark. I found
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I was reading some of Geo John’s projects and came across a crystal radio set that he built using two tuned coils. A crystal radio set refers to the type of detector used, which was once a galena crystal and a ‘catwhisker’ to find a sensitive spot on the crystal. Nowadays, that is no longer
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I captured this off a video and tried to make it a bit more readable. I think it was from Sanjev. I built it and it does work at 40 millivolts. The 2SK170 JFETs are not common, and may be difficult to obtain. Other JFETs can be used, but I haven’t tried them. I wrote
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Fellow JT experimenter Quantsuff has been experimenting with a Joule Thief using the 2SK170 JFET, and it runs at 131 millivolts (0.131V), powered by a solar PV cell lit by a table lamp. This is a very good JFET for low voltages; I made a similar circuit a while back and it ran at several
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I built a Joule Thief using a 2N7000 MOSFET with the white LED across it, a standard coil (see below) and a voltage divider connected to the gate. I was trying to find out more about the MOSFET, such as the gate bias voltage needed to make it run on a 1.5V AA cell. The
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I blogged a schematic on May 15, but it took me until now to build the schematic. I tack soldered the PSO together with the components shown, except I did not use the two diodes and two 10k resistors. First off, according to this article, to get it to oscillate, the overall voltage gain of
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