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  1. WHONOES

    Timer circuit

    Have a look at the data sheet (see link below). There are quite a few variations on the nomenclature. the 14538 is the same as the 4538. http://www.ti.com/lit/ds/symlink/cd14538b.pdf
  2. WHONOES

    Timer circuit

    You could try using a CD4538. It is to monostables in one package is very simple to use and is reliable.
  3. WHONOES

    Op amp problem ua741

    See the attachments. You will need a 24V supply minimum to achieve 10V out because of limitations of the positive output of the 741 plus the gate source voltage of the FET. As well as that, there is the variation of the Vgs of the Fet to take into account and may take a little bit of fettling...
  4. WHONOES

    You know you're a valued customer when...

    I'd ask if anyone on this forum has one that they could sell or donate!
  5. WHONOES

    Generator questions

    The output voltage of you generator will depend on 3 things. Coil inductance. Magnet field strength Rate of change (the speed at which the magnet passes your coils). Once you are armed with these facts you could make a prediction. In the unlikely event of these I would do as Alec_t suggests.
  6. WHONOES

    Soldering audio cables together

    Don't burn the insulation off. It will leave a lot of material stuck to the wire making it difficult to tin and solder. Strip it properly with wire strippers or a craft knife.
  7. WHONOES

    Soldering audio cables together

    The best solution would be to use an inline plug and socket.
  8. WHONOES

    +15V supply shorted

    Yup. I wasn't actually suggesting that oscillation was your problem, just adding my thoughts to the posts as they might be useful to someone else having issues.
  9. WHONOES

    Op amp problem ua741

    Absolutely true AK. But with a little bit of lateral thinking it is possible to get within a few milli volts of the negative rail if that is the requirement.
  10. WHONOES

    Non-inverting audio Op-Amp

    I this amplifier already in a circuit somewhere?
  11. WHONOES

    +15V supply shorted

    It is worth noting that some voltage regulators have a tendency to oscillate if its output capacitor is missing or not adequate. They tend to get fairly warm when doing so. If it is, it won't always be obvious and can lead to a wild goose chase.
  12. WHONOES

    Op amp problem ua741

    There are opamps that will go very close to the plus and minus supply rails and include 0V (ground) input in common mode and also work on a single supply but, not the venerable 741 or its derivatives.
  13. WHONOES

    B or not to B

    The IRFP460BPBF is lead free. Other than that it is the same although the "B" version does appear to be fully insulated.
  14. WHONOES

    12 MHz oscillator with a Voltage range 120V

    What do you want it for?
  15. WHONOES

    Trans former rewind

    Keeping it simple. Dismantle the transformer by removing the laminations. Take care not to bend or mutilate them as you do as this will affect their performance. Unwind the secondary counting the number of turns as you do. Divide the number of turns by 3. Using a slightly heavier gauge of wire...
  16. WHONOES

    Computer mouse circuit repair

    You are not wrong.
  17. WHONOES

    Computer mouse circuit repair

    I should imagine the board is meant to have plated through holes to maintain continuity through the board. From your photo's, it looks as though the plating has been pulled out when you have removed the switch. Unfortunately that is all to easy to do. If so, you will have to find a way to...
  18. WHONOES

    Non-inverting audio Op-Amp

    You can reduce the gain to unity by throwing away R2. If you need anything less then it will have to be a divider.
  19. WHONOES

    Help Joule Thief Circuit

    The joule thief circuit can be made to work and give a positive voltage. Just add a tertiary winding (third) winding to control the base circuit then, you can do as you please with the secondary. See attachment below.
  20. WHONOES

    2 Capacitors in parallel means less ESR?

    Yes it will.
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