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    limiting line voltage...Optocoupler vs Zeiner...suggestions?

    The zener approach sounds simpler and less expensive. Have you considered using an LED for the voltage limiter? One of the older die-type (not the newer film-type, they have higher voltage cost more and are less forgiving of static) in green will limit to 1.6-2.0V, depending on the current and...
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    LCD Backlight

    That's one way. I haven't looked at a lot of backlights, but those I've seen are series-parallel arrays two long. The 2*20 modules I have use 42 LEDs.
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    LCD Backlight

    I neglected to label the anode and cathode, but this should help.
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    non logic level multiplexar

    For SPST analog switches, there are 4016 and 4066. There are also analog line selectors like 4051, 4052, 4053. Following one of these with a unity gain amplifier should fit the bill.
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    H Bridge Driver

    I was involved in some discussion on H-bridges a little while ago. Before I start repeating myself, read a little from http://forum.microchip.com/tm.asp?m=64492 and http://forum.microchip.com/tm.asp?m=56838 . As for this application, Do you need isolation or do the motor supply and the low...
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    square wave to sine wave converter

    If you send a square wave through an integrator, you should get a triangle out. Sending that through a second integrator should give you something a sine wave with pointy peaks. I think the Exar chip ends the quest here. One more stage may improve the wave noticably. You'll have to correct...
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    Measuring Power Lines Noise

    The voltage you're reading on the neutral is proportional to the current, so there's your current probe. The only problem is that everything that's downstream of that particular breaker will contribute to your reading. LIke the image you posted- it looks like there's electronic equipment...
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    Potentiometers and computer Power Supply

    I recommend against having one reference dependant upon another. This can cause a lot of frustration when trying to adjust them. The power supply isn't likely to notice the current required by the references. And using an opamp as a unity gain follower should do a fair job of buffering the...
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    Variable Freq Drive

    GreekPIC, Go with your namesake (PIC). There is an appnote on this very subject at http://ww1.microchip.com/downloads/en/AppNotes/00843a.pdf . You may even be able to do it with one of the 14 bit cores. The PWM will almost certainly be done entirely in software, considering the change in...
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    high voltage resister devider

    I've been considering an HV probe for my DMM, but it would only be good to 20kV or so. My meter is not 10M input impedance, it varies. One time I tested it indirectly and found it to range from 9M5 to 11M. With this in mind I'd probably put it in parallel with a load resistor of 1M or less to...
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    Ask about design a Frequency Synthesizer

    I'm doing something similar with a 16c73. It'll have limited range, but will have a serial interface as well as direct and LCD.
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    regulated 12 v dc and 500 mA current o/p

    I've mentioned the fellow before, but here's a link to the circuit you describe. http://www.romanblack.com/a04.htm You may have to change Rs to get the current you want.
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    1w Luxeon led/s driver for use in car?

    There are a few variants of a switchmode regulator at http://www.romanblack.com
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    Iron-on PCB's w/ photo paper

    As for the disposal, first neutralize what you're planning to throw away. One good way to use up it's oxidizing capacity is to drop in scrap aluminum, but do it outside away from anything you value. Once it's inactive flush it down the toilet, never the sink. Flush a few more times. For...
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    nice title

    Audioguru, I think Hotwaterwizard means for it to be pronounced 'Sheik', though it is unlikely to find oil barons.
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    Ideals

    More than half the people I've asked said they made an LED blink. So did I.
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    output buffers

    I don't know if I can attach two images to one post, so here's the other idea I have. This one does not invert, and is a bit more forgiving of supply voltage. The first stage (Q1 and Q2) steers the current away from the second stage bases. The quiescent current, IRc, will flow when the output...
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    output buffers

    I'm sorry about the delay, I had a couple other things to attend to. This one is inverting. The output has resistors in the emitter legs, which are optional. I thought that for multiplexed LEDs, some current control in the buffer would be good. If this is not desirable, the resistors (Re)...
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    output buffers

    I'm interested in a parts minimal tri-state output buffer. No enable pin, just high-OC-low output from the input signal. I'm inspired by the capability of uCs to multiplex outputs, but find the use of support chips wanting. For applications like clocks and gauges the uC will spend a lot of...
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    Mains current detection

    I went looking for such a device at my local hardware store. I sure had trouble explaining the function and purpose. I finally found a vacuum cleaner with one built in, but didn't feel like buying that day. Just the same, a slave outlet would be handy. MP and Ante, I would and will use a...
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