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  1. Arouse1973

    Faulty Photodiode Reception

    We need to see the circuit diagram if possible. Adam
  2. Arouse1973

    Speed measurement

    A Simple read switch would probably work for the triggering. The interesting bit is going to be to convert the RPM of the wheel into speed. Do you want an indication of speed on a digital readout, a dial gauge or say a bar graph display? Also if you can your wheel size you will have to calibrate...
  3. Arouse1973

    Old PSU as benchtop power

    I always thought power good was just a signal telling the PC it is ok to continue, this is the grey wire. DC on is the one I thought you grounded and is the green wire. Adam
  4. Arouse1973

    Ring Modulator (dalek emulator)

    Exterminate Exterimate. Sorry had to do that
  5. Arouse1973

    How to hold the output of a variable voltage source?

    Infinite that's a bold nobel prize statment.
  6. Arouse1973

    Ring Modulator (dalek emulator)

    Bloody hell Kris is there somthing you should tell us lol
  7. Arouse1973

    Help with huge LED circuits

    Looks great. love it !
  8. Arouse1973

    Op Amp - ramp generator problem

    Great News Thanks for your support Harald, what a nice end to the week both helping someone we have never met and working together to help, makes me smile :) Adam
  9. Arouse1973

    Emergency Power Supply Schematic Diagram

    I see what you mean now.
  10. Arouse1973

    Comparator vs. Op Amp...

    Things to think about for both. 1)Stability. 2)Input offset 2)CMR. 3)Output structure. 4)Driving logic gate. 5)Differential voltage range. 6)Common mode voltage range. 7)Speed / Bandwidth Adam
  11. Arouse1973

    Op Amp - ramp generator problem

    The zener is not a perfect switch and will start to conduct before it fully avalanches say . This could be enough current to turn on the first transistor and put supply onto the 1K. this current could be over 20mA which is the max the chip can handle but the chip could have a current rating as...
  12. Arouse1973

    Emergency Power Supply Schematic Diagram

    Kris can you explain what you mean, a boost converter is just a flyback converter bootstrapped from the input voltage. All the flyback converters I have seen have transformers and boost convertors tend to have just a single inductor. Cheers Adam
  13. Arouse1973

    Single Digit LED Counter issues

    The only other thing that I can think of if everything else is as it should be. So if your input are changing then I would suggest you have damaged the chip somehow or you don't actual have a physical connection from the output of the counter to the BCD inputs.
  14. Arouse1973

    Help with synchro sawtooth generator

    I use the word strip board for the proto board you solder components to, bread board is the big plastic block thing you poke components in that don't need soldering. Also people call breadboard an SRBP board with just holes and no tracks, but people also call this matrix board. Oh god it's...
  15. Arouse1973

    Help with synchro sawtooth generator

    As long as the beam does not spend too much time out of site as this might effect the speed of your sweep for a faster trigger if needed. Adam
  16. Arouse1973

    voltage divider with diode

    Bobs right. And a high damping factor is more important from a sound perspective at low frequencies which prevents boomy bass. The damping factor can also go down quite a bit with increasing frequency due to the reactive nature of the speaker. Adam
  17. Arouse1973

    Transfer function of an opamp

    Ao in this formula is the pass band gain of the circuit G=1+R4/R3. If the circuit was a unity gain version you just replace the Ao with 1. Thanks Adam
  18. Arouse1973

    Emergency Power Supply Schematic Diagram

    Yeah Duh what was I thinking? go easy on me Kris, only been doing this a few months :) Adam
  19. Arouse1973

    Emergency Power Supply Schematic Diagram

    I think Q2 on the original diagram is used to track gate voltage changes due to temperature as both devices are the same the turn on voltage generated at the drain is used to turn on the second FET. Q3 would have probably worked for the low current in this circuit. But Q4 is still wrong...
  20. Arouse1973

    Emergency Power Supply Schematic Diagram

    Hello What battery are you using? I don't know of any 10V batteries I might be wrong. Q4 is around the wrong way I think, you will be supplying current through the body diode of the FET. The FET will always be conducting. I doubt also you will have enough voltage difference between the gate and...
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