Archive for November, 2019:

2019-11-16 Fixing a Driver Transformer With An Open Primary

Also FB group Building Transistor Radios 2019-11-16 I was working on an AM radio that had a driver transformer with an open primary. I slit open the wrap and found the tiny fine wire on the right was loose so I soldered it to the heavy wire. But it was still open. ☹️😱 So I

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2019-11-15 Build A LED Tester

Big Clive’s YouTube video Ohhh nooo! After all the trouble Big Clive went to show us how a Joule Thief works, he *digressed* to using a 9V battery! Horrors! 😱😱😱 I built a Joule Thief with a socket like he used for the LED. But the JT must not be left open circuited without the

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2019-11-12 Kicad and ExpressPCB Printed Circuit Board Software

From FB group, 2019-11-12 I hope Kicad has improved in the few years since I tried it. Then it really wasn’t a single app, it was several programs that kinda sorta did something. I didn’t expect much – it was about what I paid for it. I came to the conclusion that if I wanted

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2019-11-07 Audio Impedance Matching Box

I’ve often had to kloodge together an audio transformer, jacks and other stuff to make a medium impedance output match a low impedance headphone. But it turns into a mess of wires and parts dangling from a transformer. I thought about what I would do to make a box with the necessary stuff, like inputs,

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2019-11-05 Einstein 100 Years Ago

Einstein became famous 100 years ago.

2019-11-01 Microwave Motion Detector (BigClive)

Here is a good explanation of a microwave motion detector with a schematic. A few important things: This gadget detects *anything* that moves that interferes with microwaves. It isn’t limited to living bodies. The microwaves will go through drywall or other insulating surfaces. It will be attenuated by glass, presumably because glass has lead and

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