Latest threads in Hobby Electronics Basicsshow only best voted threads
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Power in use indicator please ?
I have a water pump in a remote location. Sometimes the pump (120 volts) li ne springs a leak and then runs all the time with the potential of burning out pump. I want to build a little circuit that...
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2 years ago
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50 | |
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Diagnosing speakers
I have a 6 speaker home theater system. However the middle 2 speakers have no sound. I checked the voltages. 0 volts when a movie is playing versus .22 Vdc when movie is not playing. Does that help at...
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2 years ago
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16 | |
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Checking capacitors
Today I received one of the roughly $ 20 component testers. Checking it out and comparing capacitors I notices a big difference in a couple of them I was using a Fluke 87, a LCR meter from China, an...
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2 years ago
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8 | |
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Solar Charging Night Light not working
Hi all, I am trying to implement a very simple solar charged night garden light. Schematics is here: Basically a solar panel charges a battery. When the solar panel output is low (at night), a joule...
24
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2 years ago
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24 | |
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Flux density
Reviewing stuff I forgot during lockdown, this is one thing I never got. H is amp-turns/meter, and having distance in the denominator suggests that it is also a measure of flux density (but without...
8
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2 years ago
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8 | |
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Small generator over-voltage
If there's a better site/forum for this question, please let me know. I have an old (mid 80's) Sears Craftsman generator - 4 cycle B&S engine & 120v, 1350W rated output. (Jeff - model 580.328172) I...
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2 years ago
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15 | |
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Why does my server's redundant supply only have 12V?
It's an old Dell R410, with supplies DPS-500RB (12V only) and D480E-S0 (12/5/3.3V). If the second one died, the first one can't make the server still run, as there's no 5V or 3.3V!
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2 years ago
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25 | |
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Power supply current?
I wish to buy a power supply delivering up to 500V for experiments with thermionic valves. What would be a suitable current?
24
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2 years ago
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24 | |
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I got a box of old parts, any chance any of it is useful?
At a fundraising event I found a very nice wood box in the electronics section. It has what appears to be a broken decades old multimeter at the top, and drawers full of parts below. There are a...
7
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3 years ago
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7 | |
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Transistor testing
I have some BC547 transistors which I want to use in a circuit, but according to this: Hook the positive lead from the multimeter to the to the EMITTER (E) of the transistor. Hook the negative meter...
15
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3 years ago
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15 | |
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Wireless phone charger
Just for fun I thought I would make a wireless phone charger. I'm not reall y going to use it but I wanted to build it and just see if it actually work ed. The circuit uses two coils and a 2n222...
5
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3 years ago
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Does a parrot's foot conduct electricity?
My pet parrot has a habit of chewing wires but never got a shock. I tested her feet with a multimeter and it was over 20Mohms. My own dry finger is 1Mohm. Are they safe from shocks due to scaly feet?
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3 years ago
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63 | |
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555 pin3 output
I've been trying out a couple of Automatic Fence Lighting circuits with a 444, 741 and ldr. I posted earlier about the circuits above , and the problem I had was that I could not get a buzzer to work...
4
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3 years ago
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Problems with 12V and 5V lines on a PC ATX supply
I said "They could even have it shut off if there was enough external load." A decent supply made by Corsair lets you take the full 850W from the 12V line. The designers of this supply are morons.
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3 years ago
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10 | |
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Schmitt Triggers
I have been looking at schmitt trigger circuits and didn't realise how many variations there are. Anyway I found this one: The author here says that by adding a 22k resistor to the bottom diagram...
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3 years ago
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32 |