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  1. (*steve*)

    How to slowdown capacitor discharge

    One important consideration if using high voltage capacitors is to step the voltage down before powering the motor. The most efficient way is to use a DC-DC converter. However, finding one with an output voltage as low as 2.4V and which also allows an input voltage of 250V will be an...
  2. (*steve*)

    Laminator for PCB's ?

    A colleague of mine had just completed building one of these. Several observations from him: 1) the material is really easy to get creases in while laminating. His solution is to laminate vertically with rollers feeding the material to both sides. 2) Use the board soon after laminating...
  3. (*steve*)

    Needing help with a 555 timer switch

    For the OP's case, the two 555 solution would work, removing the ability to reset the bistable would do the trick. note that it is important that the bistable starts in the right state. An appropriate power on reset will ensure this.
  4. (*steve*)

    Needing help with a 555 timer switch

    Yes. If you have a 555 set up as a monostable with a time period t and you send trigger pulses with < t between their falling edges, the 555 will remain triggered for ever. if it was non-retriggerable, the output would change state for time t then trigger again on receipt of the next falling...
  5. (*steve*)

    Audio amplifier using a preamp and an lm386 audio ampl

    if your amplifier is picking up mains hum and it is battery powered, you are best off looking at options to shield the circuit. The wires from the microphone to the input are probably the most likely place to pick up hum, so using shielded cable here would be my first action.
  6. (*steve*)

    Needing help with a 555 timer switch

    when referring to a monostable, "retriggerable" and "non-retriggerable" refer specifically to the behavior of the device if a trigger pulse arrives while the monostable is in its "unstable" state. If the OP has his own definition of "non-retriggerable" which differs from the conventional...
  7. (*steve*)

    Needing help with a 555 timer switch

    A 555 is retriggerable. one option is to have one 555 set up as a bistable which is triggered by your input and its output triggers the second monostable 555. when the second minostable returns to its rest state it resets the first 555, allowing I to be triggered again.
  8. (*steve*)

    Audio amplifier using a preamp and an lm386 audio ampl

    Posting the same question three times will not garner you friends. Please don't do it again.
  9. (*steve*)

    Soldering Problem

    You're probably leaving the soldering iron on the joint too long, or digging with it. This can lead to pads being removed.
  10. (*steve*)

    Constant current (or voltage) source WITHOUT semiconductors?

    you could also build a circuit with valves!
  11. (*steve*)

    Soldering Problem

    desoldering components is a skill. If you are just removing them to replace them, clipping off the leads from the component then removing the pins one by one is an easier technique. However if you want to reuse the component and not damage the board, you need to practice and possibly get told...
  12. (*steve*)

    How to modify 12-24v car phone charger?

    That's a pretty crusty looking tip on your soldering iron. I suspect this photo was taken while the iron was cold (which doesn't help). The first thing I would try is to heat it up, than using a newspaper sufficiently thick so as not to burn your fingers, draw the hot tip through the folded...
  13. (*steve*)

    Frequency Divider

    the problem is that your gate version passes D to Q while the clock is high. The other one does it as the clock goes high. the practice upshot is that your gate version is not limited to a single transition during each clock cycle
  14. (*steve*)

    Differential Amplifier - Differential Mode

    Does that mean that if the resistors were a minimum (i.e. both outputs tied to Vcc) that the gain would be at a maximum?
  15. (*steve*)

    How to modify 12-24v car phone charger?

    I agree :-)
  16. (*steve*)

    Unknown voltage of a Op amp

    So that was your question And you've shown that the answer is yes.
  17. (*steve*)

    Effectively defeating PWM on Jeep Wrangler

    I would go the cap. The PWM must be at a very low frequency if you can see noticable flicker. Any solution looking for intermediate voltages will fail if PWM is used because the power is either on or off. Be very aware that placing capacitors in parallel with LEDs can blow them up very...
  18. (*steve*)

    I need some fresh eyes

    you say there's no power getting to the board. Have you measured the power supply rails?
  19. (*steve*)

    Soldering Problem

    Wow. Let me assume the pin was soldered when you removed the chip? If so, you may have dodged a bullet. However, I recommend you improve your technique somewhat before trying this again.
  20. (*steve*)

    Korg MonoPoly not powering up.

    the next thing I would do is to check the power supply rails. This will point you in one of 2 directions. At extremis, it could be your power cable is unplugged or that the speaker wire has become disconnected. It's unlikely to be that easy though. ;)
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