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    Alternative Transistors for LM317 High Current Voltage Regulator Circuit

    I have written a blog post to to share a working circuit and PCB layout of LM317 power supply Here's the schematic from that post: The TIP2955 / 2N3055 transistor combination is reasonable to use. This PNP is larger than required, but costs little more than a smaller part. Agreed that...
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    Ammeter Tester

    Matt, It would be helpful to know the internal resistance of the meter, or the full scale current. Sometimes this is marked on the meter, else one or the other value can be measured. Care must be exercised with any measurements. If you have just a few meters to check, any computer control...
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    MC34071

    The MC34071/2/4 family appear to be upgraded LM358/324 sort of op-amps. Distributors list the MC34071 single op-amp as obsolete for all package types. So get your SMT units soon! See: http://www.onsemi.com/pub/Collateral/MC34071-D.PDF The dual and quad versions (MC34072/4) appear to still...
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    why connect a jfet gate to source?

    Thanks for the link to the schematic. To answer your question, I don't believe that Q2 in the linked schematic actually does much of anything useful. This device will conduct at all times. It will act as a relatively low value resistor. ( Small relative to the series 39k and 200k resistors.)...
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    7 Segment + DP Common Anode Display Driver IC

    To provide help more specific to your requirements, we need to know more about those requirements. It would be nice to know the exact display device you have. A link to its datasheet would be ideal, but we need at least the manufacturer and part number. How do you plan to generate the...
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    precision voltage regulator adjustable

    Raj, To really address your problem we need to know more. What sort of load must this voltage source drive? How much output current must it provide? Is the load resistive in nature? Or at least predictable? What do you have in the way of DAC or PWM outputs at your microcontroller? (...
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    why connect a jfet gate to source?

    Q2 is wired-up in a manner to produce a constant current source, but this may not be how it functions here. It would be interesting to see more of the circuit. What we do see would appear to operate entirely at large negative voltages, if Q2 is serving as a constant current source. I...
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    Trouble understanding shunt resistance for short-circuit current measurement

    This is better! The mechanical relays will work, but might be more costly, and less versatile. When driving a relay from a solid state device, you need to add a snubber across the coil to avoid excessive voltage across the coil on turn-off. A simple diode across the coil usually works. Be...
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    Floating Dc Current Source

    Raj, It is not clear from what you have said so far if you need galvanic isolation for the load, or a different polarity for the current. I think what you have already is a current source that sinks current to the common, or ground, used by the controlling computer system. It is unipolar...
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    Trouble understanding shunt resistance for short-circuit current measurement

    Thanks for posting your diagrams. Cause some eyestrain, but convey the information. There are some problems with the circuit that will keep it from working at all. And of course, I have suggestions that may or may not be helpful. I expect others will chime-in. The four ADC inputs for...
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    Trouble understanding shunt resistance for short-circuit current measurement

    Hop, I think I was agreeing with you that designing an elaborate instrumentation amplifier is not the best plan. If you want to use an LM324, better stick to applications where a simple circuit will work well enough. Getting a breadboard amp working can be very educational, though...
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    Trouble understanding shunt resistance for short-circuit current measurement

    It seems to me that you need to review your functional requirements for the entire system, create a "specification", and possibly a high level block diagram, before you become too deep in worrying about resistor precision, IC selection, and other circuit details that might not even apply to...
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    Trouble understanding shunt resistance for short-circuit current measurement

    You said The idea is to compare 4 groups of cells, all 4 measurements being taken (almost) simultaneously and repeated on a regular basis (say, every 1 minute) during the whole day. Am I correct in thinking you intend to take four sets of measurements each time? This sounds like a lot of...
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    buying a THD meter

    You should be able to make this measurement using a current transformer and a personal computer. Feed the signal into a sound input. Get yourself some audio measurement software and you are in business. Some of this software will provide a nice waveform display on the screen, separate values...
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    Need help to identify this device

    More than likely, an SCR or TRIAC. Perhaps from Teccor, and about 30 years old. Trace out the circuit for us and we can tell you what you need to use to replace it. BTW, it's better to leave the plating in the plated-through holes in the PCB! Ted
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    Substitute for MC14049 inverting hex buffer

    I imagine that the circuit will work using the 4049 as a gate driver. Of course, designing today from scratch, we would use something else. There are now parts designed for the job. The LM3524 is getting a bit long in tooth, as well. But this design looks as if it has a fair chance of...
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    I2S MCLK alignment

    More help might be forthcoming here if you can provide a manufacturer and complete part number for a specific part. Better still, a link to the datasheet where you see the things you mention. Ted
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    CMOS diffrential pair with current mirror using active loading and unipolar power supply

    Sorry to always be asking for more information, but we cannot answer your question without more information from you. Answers to my old questions would still be useful, and we obviously need to see your circuit that is working, as well. We need not only the circuit for the amplifier itself...
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    CMOS diffrential pair with current mirror using active loading and unipolar power supply

    What have you tried so-far that does not work? You might post some schematics of the circuits you have tried. Tell us your test results for each one, particularly, just how it failed to work. Is this circuit being constructed from actual components, or is it being simulated? If you are...
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    Help with N-Channel Mosfet as a switch at low voltages.

    You might want to add the load device back into the schematic. Perhaps list some parameters for it. As Bob pointed out, the circuit as posted does not make sense. But thanks for posting an otherwise clear schematic! Depending on your other requirements, you may have a good application for...
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