Latest threads in Hobby Electronics Basicsshow only best voted threads

Subject Author Posted Replies
 
Use a Ground or Lightning Rod?
Last week we had a terrific lightning storm, and it hit the TV mast, rotor, and antenna. That was witnessed by a neighbor. Although I had turned off a lot of computer equipment and unplugged quite a...
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Oh CRAP!
Now they're pulling the plug on all newsgroups, not just binaries: Please note that on or around July 15, 2009, AT&T will no longer be offering access to the Usenet netnews service. If you wish to...
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Decibel tutorial
I have created a tutorial to explain decibels. It is located here: It consists of a flash program that allows user interaction and also contains a fair amount of embedded audio explanations. The flash...
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Generate -+5V from 12V
Hi, I need to generate a symmetric +/-5V supply from a single +12V supply. I need about 150mA from the +5V side, and less than 50mA from the -5V side. I've thought about using two 7805 in the...
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how to build a clock with pulse for the hours!
Wonder if some kind person can describe how I can build a circuit that is basically a black-box (clock) that provides a short pulse - that outputs 1 pulse for 1 o'clcok 2 pulse for 2 o'clock etc? I...
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LM 393 switching soft
Hi guys, hope someone can help. I've got a LM393 on a 12v supply measuring a thermistor. I've got it switching around the right temperature but have a grey area where the output ramps up brightening...
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MacBook 13" charger circuit
I have a MacBook 13" (not under warranty). When the charger is connected it does not light or charge the battery. I have tested the battery and charger on another MacBook and they are fine. I have...
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Make X100 'scope probe from X10
I've been measuring a lot of small capacitances (C) lately, I've been using this old TEK X10 'scope probe with 8.5 pF of C. (All the new probes stink, 12 - 16 pF) But It would be nice to reduce that...
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What is the smallest physically-possible voltage that can be detected or processed given the state of today's technology?
Hi: What is the smallest physically-possible voltage that can be detected or processed given the state of today's technology? Thanks
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Is this electrolyte leakage?
Cap at top center: Or just marking? The red stuff seems to have substance to it (more than just ink)... No bulging, or leakage elsewhere.
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LTSpice and OpAmp Oscillation
I've built a discrete transistor OpAmp, and when the input was off, I saw it oscillating. So, I got interested in OpAmp oscillation and compensation. The main criterion is that a Phase shift of 180...
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LC tank circuit at resonance
hello, I have been reading on the LC parallel tank circuit. I have installed on my breadboard an inductor and a small Ac capacitor, I hooked it up to my frequency generator at 5vac. I was expecting to...
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Z80 reset circuit
I need to make up a reset circuit to reset, on power on, a Z80 (old 40-pin DIP type) and a few TTLs. I don't want to make up some circuit using TTLs and resistors, caps, etc, I simply want to buy an...
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Frequency-to-Amplitude and visa-versa conversion -- possible?
Hi: Please don=92t get upset at me. I apologize profusely for posting something similar in a different thread. However, you will notice some difference as you read. Does a device that switches...
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inductor substitution
I have an small electric motor that has some kind of speed control pcb attached to it. There are two inductors manufactured by Devalon marked 4.7uH and 10% They are the size of a 1/4 resistor and...
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