I built this “tungsten roadwork beacon” as Clive calls it, using the parts given in my schematic (photo below). I didn’t have a 6V, 90 mA lamp, so I simulated it by using three 20 ohm, 1/4 Watt resistors in series, which gives 60 ohms and 100 mA load with 6VDC. For an indicator I
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I posted the photo of the back side of the receiver (earpiece) for a Bell System telephone (either 500 or 2500) set. I said that the green blob in my photo (and the ’44A’ metal can in the wikimedia photo below) was used for reducing the volume of loud signals. Well, that’s only slightly correct.
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I found a way to make a 0.05 ohm resistor. I found some 0.1 ohm, 10W resistors and two of those in parallel will make 0.05 ohms. Voilá. The 10W is only if these 1 inch long resistors are bolted to a heatsink, so I guess they might handle 5 Watts free air. BTW, these
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Something that beginners can put on their desktop. http://nonlinear.eecs.berkeley.edu/chaos/ResistanceCalculator/resistor.htm
Last year I tried redrawing the cube in two dimensions and I could see how the vurrents were splitting but couldn’t solve it. Now here is a simpler solution that doesn’t require a lot of effort with whatever. I built the cube from 1k resistors and measured the value from corner to opposite corner, and
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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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From my FB comment Some comments say measure with a meter, but fractional ohm resistors don’t measure, or barely measure with the typical ohmmeter. Instead, you should be giving better advice. You should use the device between your ears to find the resistance. The resistor should be put in series with another resistor of
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I ordered some 22 AWG nichrome wire from goldmine-elec.com today. It’s about an ohm per foot, or 3 and a fraction ohms per meter. My plan is to make my own low value resistors for current monitoring. I often want to monitor the current in a higher power LED or input current to a Joule
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First off, I must state that the PSO is not the best solution for an audio oscillator. It uses only a single transistor, but it has a limitation that makes it put out a poor quality sine wave. As typical of the PSO, the sine wave becomes distorted because the loop gain is greater
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