Latest threads in Hobby Electronics Basicsshow only best voted threads

Subject Author Posted Replies
 
simplified converter needed for duty cycle to voltage
I need to simplify a 'duty cycle to voltage' circuit. The range it has to cover are a varying 5 volt square wave pulse with a frequency range of 40 Hertz to 400 Hertz. Once the frequency is set it...
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OT: Another Good Read
...Jim Thompson
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4 transistor discrete opamp (LTspice problem or circuit problem?)
Why doesn't this discrete 4T opamp run in LTspice at higher frequencies? It looks ok at 1Khz, but I get a 5 meg oscillation at 10K or more. There are no oscillations with the input disconnected....
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Source & Sink Capability of GPIO Pins
Is there any general specification for the Source & Sink Capability of GPIO Pins when used as outputs? ...Jim Thompson
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non-destructively finding a break in an insulated DC wire
I have a wall-wart charger that put out 4.2 V DC on a figure-8 cable just over 1 metre long. There seems to be a weak spot or intermittent break in one of the wires --- sometimes it doesn't work but...
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Timer Question
Anyone make an off-the-shelf timer that I can trigger and it'll run for X-hours then operate a relay? Or do I have to roll my own? ...Jim Thompson
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solar cell vs mili amps
does someone know the mili amps vs power vs short circut mili amps and can explane it to this dummy
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What is the capacity of twisted pair phone lines?
Where I live on Whidbey Island the local phone company, Whidbey Telecom, installed fiber optic conduit to all the customers because they anticipated the need for fiber optic cable to be able to carry...
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Pinging NEON JOHN!! need to reach John DeArmond asap!
John DeArmond, aka Neon-John Can't get the email links to work, John, I've got to reach you regarding radiation and electronics interactions. Please send me an email with an address that can reach...
 
Simulating Power Bandwidth
I'm trying to do a simulation to show power bandwidth for a (high power) OpAmp versus compensation capacitor. In the lab I would simply crank up the signal generator amplitude until the output became...
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distortion with Class B (with NFB) vs Class AB
I was shocked to see such low distortion figures on this Class B audio amplifier: Is negative feedback sufficient to eliminate crossover distortion in Class B?
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Tubes: neutralization of space-charge causes drop in tube resistance? Deionizing voltage re-combination?
ronics/CH-03.pdf "If the anode-cathode voltage is low, the electrons do not possess the nece ssary energy to cause ionisation of the gas. Therefore, the plate current flow in the tube is only due to...
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low-power audio amp basics
For some low-power audio amps, usually less than 2 Watts, I see the amplifier powered by +V and ground: For other, usually higher-powered amplifiers, I see a +/- power supply required. Do the...
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Creating sparks with a mosfet and ignition coil
I would like to generate a series of ~1000 volt sparks continuously, for several hours, using a spare automotive ignition coil I have lying around. I found this 555 circuit online: My questions: (1)...
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Why are FR4 copper clad PCB boards so expensive?
1 Kg of Copper costs around 6$ assuming you bought on the commodities marke t (per ton) however a PCB which is a thin layer of copper and epoxy-fibergl ass sells for upwards of 16$ for a few measly...
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