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  1. Arouse1973

    i give up.. lm317 + 2n2222

    I thought it strange you hadn't responded. I know it's very common not to get any responses from other members on a thread, why some of them even bother half the time god only knows. Check your Alerts settings and make sure you are sending alerts out. Cheers Adam
  2. Arouse1973

    i give up.. lm317 + 2n2222

    I thought that's what I posted for you in post #16? You haven't even acknowledge if this is suitable for you. Adam
  3. Arouse1973

    i give up.. lm317 + 2n2222

    Nope 1 Volt across R3 as it is drawing 100 mA. Thanks Adam
  4. Arouse1973

    i give up.. lm317 + 2n2222

    This circuit will give you a constant 100 mA with R2 as 1K and R1 as 270R, from a load of 20R to 1R. Change R1 and R2 to increase the max current range. Thanks Adam
  5. Arouse1973

    Add DC offset to AC signal

    And don't forget he might need a negative supply for the opamp also which could complicate matters. Adam
  6. Arouse1973

    Add DC offset to AC signal

    Feed the signal through a capacitor and onto the centre of a potential divider or onto a voltage source with a series resistor set for 2.5 V. Adam
  7. Arouse1973

    i give up.. lm317 + 2n2222

    And I guess you want to use this as a variable current source? Adam
  8. Arouse1973

    i give up.. lm317 + 2n2222

    Yes it's the sharp turn on slope (Trans-conductance) of the transistor. Let me have a play and see if I can come up with anything. I am working at the moment so won't be until later. I guess the problem will be solved by then :). That's the problem living in the UK, most of the US guys have...
  9. Arouse1973

    i give up.. lm317 + 2n2222

    Are you asking if you can replace the resistor with a transdiode configuration or similar? Or are you asking if it can be done using a transistor as the current limiting element? Adam
  10. Arouse1973

    Watchdog Timers

    Colin, just told you above?
  11. Arouse1973

    Phase shift

    Hi LvW, I thought to my self LvW will say all pass filter :). I used this approach because the building blocks can be broken down and easily understood for a beginner. You never know he might find all pass filters easier to understand. And yes any op-amp can be used your right ak. I wanted the...
  12. Arouse1973

    Energy Monitoring (Formulas and methods help)

    Yes Harald your right. I was guessing he wouldn't want to worry about this sort of thing. Maybe he does? Adam
  13. Arouse1973

    Phase shift

    Why don't you have a look and you tell me what you think might work. Download LT Spice and copy my diagram and have a go yourself. It's more fun that way. Adam
  14. Arouse1973

    Phase shift

    The circuit I gave you is for 120º. You can add more RC and buffer stages for greater phase difference. Adam
  15. Arouse1973

    Phase shift

    Phi = tan^-1(XC/R) or Phi = 360*fo*dt. But this will only get you close, you will have to adjust the resistor values to get it right. When I did the calculations the circuit didn't produce the desired phase shift so I had to manually change them to get it right, you will need to adjust the...
  16. Arouse1973

    Simple Circuit Problem

    Ok got it now Bob. Thanks Adam
  17. Arouse1973

    Simple Circuit Problem

    Hello What do you mean by does not effect the circuit. What do you want it to do? Adam
  18. Arouse1973

    Phase shift

    Remember this is an example, you would be able to use other op-amps, depends what you have lying around. Linear op-amp can be quite expensive. Adam
  19. Arouse1973

    Phase shift

    Thank-you. Here is a simple way to do it. It would be best to make R1, R2 and R4 variable. You may get quite a bit of variation over temperature so choose good quality capacitors and resistors. Adam
  20. Arouse1973

    Phase shift

    Give me a moment Adam
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