Archive for January, 2017:

2017-01-22 FM Regenerative Receiver

I’ve been building another FM regenerative receiver. This one is supposed to use a BF244 JFET. But they were declared obsolete years ago, and aren’t available in quantities at a reasonable price. So I ordered some 2N3819 JFETs from Mouser and got them a few days ago. The 2N3819 is also a VHF JFET, so

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2017-01-18 Simulating An Analog Meter

A detector or discriminator in an electronic device might need to be adjusted to a very few points on a scale of a hundred or more points.  A digital indicator typically indicates only a fraction of that, possibly 16 points.  This is why the analog meter is still useful: it can indicate a small change

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From email sent by Peter, 2017-01-17 Good to hear from you, Peter.  I forgot about telling you that last year, I wasn’t able to read a message you sent me.  I don’t remember why. I apologize for not replying. I wrote this up in a blog, but the blog isn’t accessible right now.  So I’m

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2017-01-15 Tuned Circuit Tester

I’m building a tuned circuit tester, which is a Franklin Oscillator without the parallel tuned circuit.  I based it on the schematic I found at this URL.  The first amp is a JFET in common drain or source follower configuration, which then drives the 2nd stage, a PNP transistor in common base configuration, so there

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This is a link to my pictures I posted. watsonspics Pictures, for the most part, of schematics I’ve drawn, using ExpressPCB, free software. There is little or no text. A few may have been drawn by others. Those from Quantsuff ( have a QS in the name. I’ve received permission from QS to use them.

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2009-01-10 Experimental Joule Thief

Date 2017-01-12 Link to Experimental Joule Thief

2017-01-10 Work Light

Here’s a shot of one of my very bright work lights.  It’s a 10 watt multi chip LED mounted on a heat sink, which gets a bit warm.  I mounted the heat sink on a piece of 6 AWG bare copper wire which lets me reposition the light a bit. It’s a daylight color temperature,

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2017-01-04 ASCII Chart

I tried posting this on Facebutt, but it thinks this single image .GIF is a movie!  So I’m putting it where all can get it.

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