Latest threads in Hobby Electronics Basicsshow only best voted threads

Subject Author Posted Replies
 
555 timer cookbook
Does anyone know a good cookbook for 555 timer? Thanks.
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Power Supply for a portable audio device
Hi I'm designing the power supply for a portable audio device. It has a SHARC DSP, some interface logic and amplifiers. I need several voltage sources: - 1.2V DSP core - 3.3V DSP digital interface -...
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Solar Lighting
I know it would be easier to buy a new one, but I want to learn about this. We have a box that charges 2 AAs during the day with a little photovoltaic cell, then illuminates our house numbers (yellow...
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Engineering Mathematics
Hi Im about to start my last year at uni and im trying to find a good web site that will consider answering some mind bending maths questions in fourier series, z-transforms and laplace. A few times...
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Re : Power Line Noise Reduction for Medical Device
Hi, Can anyone suggest a site which has information on power line noise reduction ? Perhaps some projects on toroid transformer power supply design for medical device ? Thanks Ken
 
Transformer and Frequency
Hello, Short question: Why is it not possible to use an "normal" transformer for high frequency like 20 kHz? Why should I use ferrite? I thought it should work even better with a higher frequency??...
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A question of sound knowledge
A student adds a sound output feature to their design using a small sounder (about the size of your little finger) driven by a logic output from a microcontroller. The table of frequencies look like...
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Unstable Switch mode supply
Hi. I have used the mic2183 chip as a switch mode power supply. I runs in stable mode until 12.15V, but suddently goes unstable at 12.2V and above. I have configured it for 3.3V with the voltage...
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Sensors
Help! I'm trying to build something which will measure the force something like a hammer hits an object. So, for example, I hit this thing and it says 78.4 PSI I'm not a technical person whatsoever so...
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eprom failure modes
I came across a new one today: eprom (27c512) programs fine, verifies fine, runs like crap. lots of errors. Same code in an emulator runs fine. Same code read back into the programmer and verified...
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passive mobile phone repeater
Asking mostly out of curiosity on this one. Some friends of mine live in a place in the mountains in Southern Spain. They can receive mobile phone calls a few hundred yards from their house, on the...
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antenna help
New to group. Hope this isn't too lame for folks- I have a cheap 'boombox' radio in my garage, and would like to improve the reception. It has the standard extendable antenna on it, but doesn't...
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Capacitor codes help
Hi! I have some surface-mount capacitors I need to replace. I don't really understand the codes on them, despite looking up many sets of SMD capacitor coding conventions on the net. Is the first...
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PWM with SG3525
Hi, could anyone help me with SG3525? I have a PWM circuit with SG3525 and need to modify the circuit so that I can get ~0.2 Hz cycle period. This is very slow compared to most of the circuits that I...
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ESD level measurement
Can zener diode be used as ESD suppressor? It is fast enough to shunt ESD to ground?
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