Archive for the ‘Transistors’ Category:

2018-06-14 The 9012, 9013, 9014, 9015, 9018 And Similar Transistors

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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2018-01-01 H N Y! Old Germanium Transistors Lose Gain As They Age

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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2017-12-04 Converting Tube Set to Transistors 

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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2017-09-10 How Long Can An Arduino Circuit Last?

My answer to a FB Arduino group question on Sept 17 Dan Rogers has the right idea.  The protoboard, with all the holes in it, was never meant to be permanent.  The contacts in each hole lose their springiness as they are used to hold wires.  The contacts can become intermittent after awhile.  As time

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2017-08-19 Emitter Base Breakdown Can Damage Transistor 

From YT reply to Neilgn  2017-08-20 Take any NPN transistor and measure the gain, and write it down.  Then put a 1k resistor in series with the transistor’s emitter and connect the emitter to positive and base to negative of a power supply.  Adjust the voltage until 2 or 3 volts are across the 1k

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2017-08-15 1950s Astor 7 Transistor Radio

2016-11-21 Goldmine Giant TO92 Semiconductor Asstmt G21402

I got a few of these just to satisfy my curiosity, and to waste ten bucks each and waste time sorting the transistors into piles of the same number. My general observations Most of the datasheets for these transistors can be found online. Most of the transistors are PNP.  I got several dozen, maybe a

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2016-10-03 Ordered Thru Hole Transistors

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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2016-09-28 Battery keeps Joule Thief Lit

I put this AA cell, which measured 1.3 volts – ‘dead’ – on one of my germanium Joule Thiefs more than a week ago. It was glowing very brightly for a few days. For the last few days, it has been weakly glowing, and the Kirkland AA cell is still hanging in there, even though

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2016-04-18 Coil For FM Microphone Bug Transmitter

I’ve built an FM microphone bug or transmitter before, but it’s been a very long time since I wound coils for one.  Long ago I would wind too many turns on the coil and try it out.  The usual outcome was the bug would be transmitting somewhere in the low TV channels 5 or 6,

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