Archive for the ‘Transistors’ Category:

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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2015-07-08 KPC AKA Key Product Characteristics

This is about electronics components, despite this off-topic intro. Last night I watched a Frontline episode on PBS about the drug resistant superbugs that are resistant to antibiotics.  They talked about one of the genes that causes this drug resistance; it produces an enzyme called klebsiella pneumoniae carbapenemase or KPC. I searched for KPC online

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2013-10-22 Transistor Behavior In A Joule Thief

I was reading some of the thread over at OU about transistor behavior.  The discussion was about the BC337-25 and the 13003, which is often found in CFL bulbs.  One poster said the 13003 was rated at 1 amp, and the BC337-25 was rated at 0.8 amps.  But in the Joule Thief the BC337-25 drew

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2013-06-26Germanium Joule Thief Uses a 2N404

This is one of those Joule Thiefs that uses an old germanium 2N404.  But I got them from a German seller on eBay, and I have a suspicion that they were made within the last decade or so, probably by one of the makers in the former soviet bloc countries.  I’ve measured true 2N404s and

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