Latest threads in Hobby Electronics Basicsshow only best voted threads
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override timer in bathroom fan
Hi there I have a bathroom fan which turns on whenever the lights turned on. After the lights is off again it continues for 2-32 minutes (can be adjusted on a small potmeter). It also turns on if the...
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14 years ago
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Gerber files
I've been designing and making PCBs for my own use for almost 40 years now. The few times I needed more than a couple of units, I had the pattern printed by local silk-screen printers. It's only...
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14 years ago
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Signal Integrity for PCB Designers
Hello friends, Here is the tutorial on Signal Integrity available for free online. tutorial is intended for printed circuit board designers who wish to get an insight into the design of High Speed...
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14 years ago
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How to make a flashlight reflector?
My powerful LED spotlight has a highly focused beam and I would like to make it more like a floodlight by changing the reflector (or however). Hopefully the light can be projected as a uniform spot at...
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14 years ago
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Signal Integrity Quiz
Here are some set of signal integrity quiz taken from the book "Signal Integrity for PCB Designers" . See How many you get correct.
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14 years ago
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antenna grounding
I'm about to get of the cable tv merry go round and am installing an antenna on my roof. The problem is that the service entrance for my coax is on the side of the house and the most direct downward...
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14 years ago
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AC DC Power supply
I need to power a Bill Changer acceptor. This is just the part the accepts the bills. It requires +5VDC, +12VDC, -12VDC AND 6VAC. These voltages all have the same single ground wire. How do I recreate...
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14 years ago
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How supply power for changing number of LED?
A friend wants to use some LEDs in something she is designing. She may use 5 LEDs or she may use 20 LEDs. It may even turn out she uses 50 LEDs. Would the resistence of the dropping resistor need to...
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14 years ago
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SMPS for audio amps
This is probably a silly question with an obvious answer to those who know: Why are audio amplifiers seldom powered with switched-mode power supplies? The common exceptions I know of are in cases...
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14 years ago
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120 volts ok in 100 volt extension cord?
I bought a 100 volt/120 volt step up/down transformer for some equipment I have in Japan. There is only one outlet on the transformer. The extension cords here say '100 volts' on them. It is okay to...
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14 years ago
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Design of Electronic Vehicle Anti-theft Gadget
See for details
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14 years ago
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Did a BT135 SCR exist?
I live in a remote place where it's often impractical to try to get the exact part I want, either for replacement or for a new project, and that was even more so 15-20 years ago when I was still...
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14 years ago
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Ultra-powerful headlamp using LEDs?
That inverter is certainly light enough, maybe efficient enough. I guess the question would be whether that adaptation would produce a high power spotlight for normal use. No, I thought maybe the 36 V...
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14 years ago
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urgent need OSRAM SFH480-2/3
Hy All, i need urgently 10.000pcs of OSRAM SFH480-2/3. Can you help me ? Any links of smart brokers ? thanks in advance maurizio
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14 years ago
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soundcard problem
This is a query about a good brand soundcard. It distorts any externally input recording, whether from radio, deck etc. It sounds like satan is speaking to me. However, the audio output is ok if the...
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14 years ago
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