Latest threads in Hobby Electronics Basicsshow only best voted threads
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Old Anelex power supply: AC on the DC
This huge, ancient power supply made by Anelex has been serving from under my shed workshop bench for about 25 years: It supplies a few projects around the house and garden and I generally just ignore...
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5 years ago
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DC cable puzzle
Tidying up my shed workshop I got an electric shock from a cable pair that had earlier been disconnected from its 14V DC power supply. So I'd expect it to have virtually zero voltage across it, apart...
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5 years ago
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MC6840 Projects????
Any suggestions for projects I could do that involves the Motorola MC6840 p rogrammable timer module? I just received a peripheral for the Apple II tha t has this chip onboard. It basically allows for...
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5 years ago
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VOX- Voice operated Relay with mods.
I'm starting to develop a VOX circuit to solve the following problem. Wife got new smart phone after flip phone went in water. We're on a boat. Wife's phone is inside now, she's outside working, can't...
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5 years ago
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MOSFET switch - sanity check
I have a Milwaukee 12v variable speed tool with a bad control board. Rather than replace the board, I'm planning to just use a switch for single (full) speed. But the switches that I have & will fit...
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5 years ago
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8 | |
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Re: film vs CMOS
You'd have to compare the format size of film. 70 mm film is probably better than most digital cameras can resolve. (excluding some spacecraft of course) The slower the film the better the resolution...
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5 years ago
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Transformerless power supply
Is it reasonable/possible to build an 8 amp 20 V transformerless power supply from a 120Vac line. I calculate about 180uf plus or minus depending on other components. Maybe 9- 20uf caps in parallel?...
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5 years ago
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Is Class 1 laser safe enough for baby eyes?
I meant, what if someone accidentally shine Class 1 laser into a baby's eyes? Would it hurt retina and leave a permanent damage? I know ... I know... it should NOT happen. Adults are supposed to be...
3
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5 years ago
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3 | |
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Formula for calculating run time of apc ?
I am looking for a formula for calculating the run time of my APC battery system. I did a search but what I found required a particular model of apc. Total watts of computer and monitor is about 120...
3
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5 years ago
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3 | |
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An idea that may be of some use
I needed a small light to light some steps from my deck to the ground and in a few other places. I already had a 12V system outside. For a cheap and dirty light I took a plastic test tube...
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5 years ago
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three terminal volt regulator
Hi all, Simple question. Some 1/2 amp LM7805 is obselete (TO-220 pac) I need a replacement. So either a 1 amp 7805 or a LM340 Is there any (practical) difference between the two? (besides the price.)...
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5 years ago
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mosfet bias question
I plan to use a mosfet in a dawn to dusk switching circuit with a 12V regulated power supply. In the application notes they give the gate source absolute maximum voltage as +/- 10V Gate to Source....
3
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5 years ago
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juice the movie
Looks interesting. -- John Larkin Highland Technology, Inc lunatic fringe electronics
1
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5 years ago
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Sanity check for a cheap DVM
I'd like to check an old Radio Shack DVM for accuracy around 5 volts DC. On a brand-new cr2032 coin cell it measures 3.25 volts open circuit, about 3.15 volts with a 3 kohm load. That's rather high...
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5 years ago
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Suppress transients on old burglar alarm
My 20 year old burglar alarm control has developed a fault that I've spent the last couple of days trying to fix. Before I ditch it and go through the hassle of installing a new one I'm seeking help...
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5 years ago
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