Search results

Search Forums New Posts
  1. Arouse1973

    Help with synchro sawtooth generator

    I don't see any issues with modifying your circuit to work using NPN transistors. You might have to tweak a few values to get it to work. I assume this circuit is your original saw tooth oscillator. Does it have to run on a high voltage to control the CRT? or is this done by another circuit. Adam
  2. Arouse1973

    Transfer function of an opamp

    This is a Sallen Key LP filter. Here is my drawing and transfer function, I think this is right. Adam
  3. Arouse1973

    SMPS boost regulator using a schmitt trigger oscillator

    Good one Steve, I use that sort of oscillator all the time in non critical timing applications. I did something similar a few years back when I made use of the high voltage produced by the coil to charge up a capacitor for an electro magnet. Adam
  4. Arouse1973

    Oxygen machine back up power

    What is the Amp hour rating of the lawn mower battery. This is a feasible project and it sounds like the battery dropped below 11V and the step up regulator drew too much current trying to produce 18V and the cycle continued until the fuse blew. Adam
  5. Arouse1973

    Help with synchro sawtooth generator

    can you use a free running osc? Here is a simple PUT osc I have drawn for you if it's of any help. Adam
  6. Arouse1973

    Help with huge LED circuits

    Connecting too many in series might not be acceptable if one LED goes OC then the whole string goes out. And too many in parallel as Bob mentioned will draw a lot of current. There is another option and that is drive series parallel chains with a constant current and cross connect the LEDs so if...
  7. Arouse1973

    Single Digit LED Counter issues

    You are trying to run a BCD to seven segment display who input to the BCD IC is in binary counting mode. I think you might need to connect pin 12 and 14 BCD mode and input goes into pin 1. Thanks Adam
  8. Arouse1973

    help with a 4017

    Can't you just connect a push button switch to the rest pin, ensuring a high level for reset. Or do you want it to do this automatically? Adam
  9. Arouse1973

    Connecting two battery pack in parallel with a MOSFET

    Your right about R3. But somthing looks strange about your circuit. Its the FET looks like its supose to supply power but its connected to the minus of the battery. Adam
  10. Arouse1973

    Capacitors Change impedance?

    Simmon Voltage isn't a substance it does not have any mass it can't flow anywhere as Steve said above it's dose not pass through anything. Current how ever is full of charged particles which do have mass and can be moved. Voltage is the change in electric potential energy per unit charge and...
  11. Arouse1973

    Virtual grounds

    You don't need a +/- supply. Just set a half supply bias point on the input of the amplifier and then AC couple the signals in and out. Do you have a circuit diagram you are going to use. Adam
  12. Arouse1973

    Phase shift full bridge SMPS problems?

    Yes and no
  13. Arouse1973

    Homemade High Amp Inverter Power Supply

    An inverter takes DC voltage and converts it do AC. I don't think this is what you need is it? Adam
  14. Arouse1973

    Capacitors Change impedance?

    Ah yes of course I misunderstood the question. He asked the question Is there any difference between an AC waveform VS a Varying DC voltage? Adam
  15. Arouse1973

    Capacitors Change impedance?

    How's that Bob. If I have a resistor across a PSU with a current meter in series and I vary the voltage knob up and down, varying the dc is what your saying I'll see the current meter change polarity? Or is this not what varying dc is. Thanks Adam
  16. Arouse1973

    Capacitors Change impedance?

    Yes a lot. An AC waveform is just what it says Alternating current. That means the current is in one direction and then it reverses and goes in the opposite direction. For this to happen the voltage connected to a load will need to go positive and then return to 0V and then go negative...
  17. Arouse1973

    Capacitors Change impedance?

    A capacitor does not pass anything apart from a small leakage current. It has a dielectric which blocks the flow of charge whether DC or AC. A capacitor uses displacement currents to work by pushing or pulling of the charges on the plates creating a charge imbalance between the plates. This...
  18. Arouse1973

    Relay Problem

    Remove the 100R and connect the collector to +V. You need two potential dividers connected from +V to 0V as Duke mentioned and one will contain your NTC connected to 0V. Centre tap them to the inputs of the Op-amp as in your first diagram. I don't know how well the hysteresis resistor will work...
  19. Arouse1973

    Voltage Regulator +Negative Voltage Generator

    That's an interesting suggestion, never done that before. What is the max current output and what would the load regulation be like? Adam
  20. Arouse1973

    Adjustable Voltage Regulator

    I think I worked this out for you earlier. 2000R and 540R = 5.98V Adam
Top