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  1. A

    Design new 0 to 30V power supply.

    I was afraid this would come up any moment now. Sure, but I would like to have the digital front-end as a retrofit. We could give different SW versions for different trafos. Try adding some real-life ESR to C7. I noticed you have eliminated the pot. divider for the current threshold...
  2. A

    Voltage Controlled Switch

    Sorry, I know it is important to you.  :P ;D
  3. A

    Voltage Controlled Switch

    You can use a comparator to sense when the voltage has exceeded say 3.2V, and then the output from that will drive a relay, possibly via a transistor. Have a look here http://home.cogeco.ca/~rpaisley4/Comparators.html Let us know if you need help designing it.
  4. A

    Design new 0 to 30V power supply.

    If I haven't missed anything, your schematic will have the same outcome. You are also using full-wave all the time. Your schematic is using one diode less, but is using a changeover relay which might have speed implications; during the switchover there will be no power delivered to the tank...
  5. A

    Design new 0 to 30V power supply.

    Thanks PICMaster. I can't believe they used an R2R ladder for a DAC when they had an MCU with PWM... ::)
  6. A

    Design new 0 to 30V power supply.

    I have never built it either. Can yu point us top any reviews? One MOSFET M1 to switch in the bridge rectifier if a high output volatge is required thus effectively adding both secondary coil voltages. When M1 is OFF, only one winding is offering power through D5 at any time. Although I haven't...
  7. A

    precision photoemission assessment.

    Here is a hard question: What magnitude of current is expected under 5 Volts across your goo?
  8. A

    circuit help

    Please could you attach your circuit diagrams to the post instead of a hosting site? You can do this by clicking on 'additional options'.
  9. A

    Design new 0 to 30V power supply.

    Come on Hero, if you don't stop posting I will never go to bed and it is GMT+2 here  :o Besides, I am supposed to be away for Christmas. ::) Maybe it is worth adding a capacitor in series with the gate of M2, M3. This will waste some gate turn-on volatge (depending on capacitance ratios) but...
  10. A

    Design new 0 to 30V power supply.

    I remembered this: http://www.elektor.com/magazines/2001/november/digital-benchtop-power-supply-(1).54823.lynkx http://www.elektor.com/magazines/2001/december/digital-bechtop-power-supply-(2).54867.lynkx I have both articles, maybe we can pull some ideas or tips. Let me know if interested.
  11. A

    Design new 0 to 30V power supply.

    5A it is then. I have obviously looked on Google and IRF.The closest matches are the IRLR3915PBF from IRF, which  comes in a D-pak and the IRLU3915PBF which comes in an I-pak. Where did you get the TO-220 pack? Meh, I am sure we will find a candidate. I agree, power dissipation is the limiting...
  12. A

    Design new 0 to 30V power supply.

    I agree with PICmaster that most projects stay below 12V or so, but the higher the output voltage range, the better. That said, I do realise that with a clean design like this, increasing the output voltage is quickly limited by factors such as op-amp supplies. This design must remain clean to...
  13. A

    Design new 0 to 30V power supply.

    How much current can you draw without a total redesign of the topology? By upgrading all components in the main current path we can easily get >5A. This will be very useful. 10A would be ideal. I think you meant Vout = Vref*5.1 + Vref = 6.1*Vref = 30.5V I was thinking of digipots as a...
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    Please recommend a Good Electronics Book

    I should also say that for circuit analysis (ac and dc) using passive components an excellent book is this: http://www.amazon.co.uk/Introductory-Circuit-Analysis-Robert-Boylestad/dp/0131988263/ref=sr_1_1?ie=UTF8&s=books&qid=1262006087&sr=8-1
  15. A

    Design new 0 to 30V power supply.

    I have associated all the file names and all the symbols load correctly. However I get the following error. See attached. Any ideas? Could you post your universalopamp.sub file?
  16. A

    Design new 0 to 30V power supply.

    Right, I will give them a try. In the meanwhile, what are the output specs of the project? 0-30V 0-3A? I was thinking, since you have engaged into designinmg a new one why not juice it up a little bit, say 50V 5A? I was also thinking how nice a digital front-end would look like, a small LCD...
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    Design new 0 to 30V power supply.

    Ok, we need the universal op-amp asy and the sub file it points at. Also, the upside-down op-amp asy and the sub file it points at if different. Zip and attach if possible.
  18. A

    Design new 0 to 30V power supply.

    My main concern was latch-up of switch-mode PSU controllers when a bath-tub voltage input is applied, hence the delay. I think that the actual delay time will require experimentation in the particular application. Most circuits will not mind whatsoever, maybe a few MCU design will fail to reset...
  19. A

    Design new 0 to 30V power supply.

    A few 10s of ms I would think. How about a capacitor between the output pin of U2 and ground through a variable resistor? No further modifications needed. You can cover a huge range with a reasonably sized capacitor as you can always set R=0 with the variable resistor. Wiper debouncing will be...
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    precision photoemission assessment.

    You will have free electrons but you will not have current. You will need to accelerate them in an electrostatic field. The current integrator will integrate the tiny current over time, thus measuring charge. If you know the time, you can work out the number of electrons freed. The current...
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