From FB group Building Transistor Radios For those who don’t want to or can’t use a JFET for high input impedance, you can use a regular transistor or two and bootstrapping to get a 10 Megohm high input impedance amplifier. This is from “Common Collector Amplifiers”, Electronics Now, Oct. 1993, found at americanradiohistory.com. For RFs,
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From FB group Building Transistor Radios Nick Cook Have you found the reason for the failure of the 2N176? You could use the NTE equivalents NTE104 or NTE121. These may be expensive but they are the substitutes. But you have to make sure that the new one doesn’t burn out. You should be able to
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From a FB group Building Transistor Radios Markku Vuorensivu Tell me more! I’m all ears! I got a thousand 2N3904 BJTs from Mouser, and ten packs of 100 from eBay. I selected a dozen from each and measured their current gain using two methods: a cheap DMM, and a ‘transistor tester’ which has the ZIF
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From the FB group Building Transistor Radios Willie Barnett The generic 901x series are very cheap jellybean transistors used in consumer electronics, typically made in Asia. The 901x was preceded by C, but other companies used other prefixes such a S901x for Fairchild (now ON Semi), or CC901x, or even MPS901x or MMBT for surface
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This is a link to telecomm information on Tomi Engdahl’s epanorama.net. http://www.epanorama.net/circuits/teleinterface.html#hybrid
I’ve had several LED purchases that were LEDs of poor quality, actually factory rejects. The sellers may not have known that the LEDs had “chipped chips” missing a piece, or bubbles or inclusions, but even more commonly, the LED chip is off center so the beam pattern is distorted. I let the sellers know, and
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Happy New Year! I replied to a comment by George Glavas on FB group Vintage Transistor Radios George Glavas I’ve never read any documents to back up your claim that “…germanium transistors lose gain as they age.” I think that people believe this because old equipment has lost gain. But all of the problems I’ve
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From FB group Electronics Hobbyists, regarding the Zenith Royal 500 radios. Clyde Hendrickson There are two 50 uF, 10V electrolytic capacitors under the battery holder. Replace them with 47 uF, 10 or 16 volts. There is also a smaller capacitor next to the other, it might be a 3 uF, or a 16 uF, 10V.
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From FB group Vintage Transistor Radios I’ve considered converting a tube set to transistors. The problem is getting tube bases that aren’t sharp and breakable glass. Some old electronics used tube base type plugs for relays and plug-in modules. Then there is the problem of dealing with the higher voltage. Transistors can handle 300V, but
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