Here in Southern California, there is no need for a fireplace, but many houses have them. The residents that have them probably don’t use their fireplace much, since they are very inefficient, and if they burn wood or logs, it can cost quite a bit. Not to mention they would be a big contributor to
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A long time ago I came across this schematic of a Surf Synthresizer circuit. I remember reading something about this earlier, and I wanted to build one just to see if it actually worked. It’s a set of three astable multivibrators with their output voltages summed and low pass filtered, and the result is used
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I built this circuit long ago and I can’t remember what I intended it to be used for. It’s kind of different. The CdS photocell is glued into the end of a 3/8 inch O.D. by 1 inch long piece of black plastic, probably cut from the body of a cheap ball point pen. This
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See my General note at the bottom for some info on audio compressors in general. I had this hand drawn schematic in my SCH files folder, dated from 8 years ago. The actual schematic was from “E.A.” dated 1968. I can’t figure out what E.A. is. I would imagine that the E stands for electronics,
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This came out of a box of junk that had accumulated for a long time in my garage. So long a time that I’ve no recollection of what it is or where it came from. I looked at it and thought that it was a temperature sensor because it was mounted on a bracket that
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In the world of Electronics, as in the Real World, there are those who try to manipulate the truth to take advantage of those who have a limited understanding of its underlying principles. We will call these manipulators scammers. One scam that I often see is when an experimenter tries to get a LED circuit
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I found this schematic of a hearing aid on a newer website called Talking Electronics, and it looked familiar. I checked the one on RedCircuits.com, and found that they are identical, other than the copycat has gone to some lengths to pretty it up with color and graphics. I know that this particular schematic has
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2011 Jun 30 Germanium Supercharged JT Note: links are broken until I replace them. Peter asked me if my Supercharged Joule Thief would be a good circuit to use with AC128 germanium transistors. But I admitted that I had never tried using germanium transistors in a SJT. So I took a SJT that was already
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I blogged this a long time ago, but my old blog is gone, so here it is again. I unsoldered a large number of these 600 ohm hybrid transformers from PBX boards. Each transformer has four 600 ohm windings, and is used to interface to the PSTN (telephone central office). Notice that there is a
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I bought some cheap LEDs from a vendor on eBay, and found that most of them had air bubbles inside of the clear epoxy that makes the lens. This causes the light to scatter, and the LED will not meet the specifications that are given for the light beam output. They still put out bright
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