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  1. (*steve*)

    I need a voltage follower with >= 1Amp output for experiments

    Best of luck.
  2. (*steve*)

    Power Dissipation Across A Transistor In Cutoff

    Absolutely not. Leave it like it is. There will be some difference, but not much.
  3. (*steve*)

    Current Regulator

    This will limit the current: Assuming the regulator variable with a nominal 1.25V output: Vout at 0A is 1.25 * (R1 + R2)/R2 Iout (short circuit) is 1.25/R3 There is a linear relationship between these points. If you're planning to charge a 12V lead acid battery, I'd set Vout as 14V and...
  4. (*steve*)

    Power Dissipation Across A Transistor In Cutoff

    Several things... The red dots indicate where you didn't join nodes correctly (you did that several places) The input is best as a sawtooth. This is a bit tricky. I've fixed both of these here. You can see the voltages on the circuit and on the scope traces. If you stop the simulation you...
  5. (*steve*)

    Light therapy device

    Section 3. The table of contents terms you that constant current drivers are there
  6. (*steve*)

    8 Year old Introduction to Electronics

    If be more happy with AA cells. If you purchase cheap cells in bulk packs they will be less likely to be dangerous even if shorted. You can purchase coloured leads with crocodile clips on the ends. The would be ideal for connecting things up.
  7. (*steve*)

    Power Dissipation Across A Transistor In Cutoff

    Draw the circuit in falstad again, export it and I will see what you did wrong.
  8. (*steve*)

    Power Dissipation Across A Transistor In Cutoff

    Have you simulated the circuit to see what happens?
  9. (*steve*)

    Power Dissipation Across A Transistor In Cutoff

    We are just going around in circles. You are asking questions that have already been asked and answered.
  10. (*steve*)

    Power Dissipation Across A Transistor In Cutoff

    No, I don't think that is correct. I don't think the supply could be damaged "which pulls the output low when is in the saturation mode" is probably incorrect after the word "low" You need to do more study before attempting this homework question. You are lacking a great deal of fundamental...
  11. (*steve*)

    Power Dissipation Across A Transistor In Cutoff

    Sorry, post 74
  12. (*steve*)

    Current Regulator

    Take a look in the LED resource. There is a simple constant current source that can drop less than 1V. For lower drops you need more exotic circuits.
  13. (*steve*)

    Current Regulator

    Current regulators require something to sense the current. Most methods of doing this will incur some voltage drop, even if it is only 0.1V.
  14. (*steve*)

    Arduino ide for commercial product development

    As long as you comply with the lgpl you're free to proceed.
  15. (*steve*)

    Brake light flasher (555 - based) circuit works on breadboard, but not PCB

    There's a reasonable chance that the noisy power supply in a vehicle is upsetting the circuit. There is a similar thread running at the moment about indicators on a 6V system. A similar solution might help here too. See here. In your case a 16V zener would probably be the right value.
  16. (*steve*)

    Light therapy device

    Sorry, I multiplied the 100mA by 2 twice. 500mA should be fine. Don't go lower than 250mA. Look in the LED resource. The is a constant current driver in there that will do the trick. It consists of 2 transistors and 2 resistors. One of the transistors will need to have a small heatsink...
  17. (*steve*)

    Problem with 555 timer

    Discharging the 100uF capacitor through the discharge pin could easily kill the transistor. Check you don't have continuity between pin 1 and 7 now.
  18. (*steve*)

    Darlington pair false triggering.....

    Add a high value resistor (perhaps 10k) between the base (1) and emitter(3) of your "darling tone pairs" (they're darlington pairs). This should not be necessary because the TIP122 are supposed to have this internally. The leakage current of the TIP122 is quite high. Perhaps you can use...
  19. (*steve*)

    How To Detect When A Line Goes Low

    That seems quite complex. I'd need more information about how the indicator switches work to be able to suggest something better though.
  20. (*steve*)

    How To Detect When A Line Goes Low

    That circuit has the potential to short out your battery, or at the very least flatten your battery.
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