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  1. Hero999

    Portable charger?!

    It uses a boost converter to get 5V from the little AA battery. This is a silly idea because AA batteries are expensive compared to recharging the phone and if you use rechargeables you might as well just charge the phone in the first place. What a complete and utter waste of money? You'd have...
  2. Hero999

    inverter and transformer rating....

    No it doesn't. The input power cannot be any greater than 6W because the fuse is 0.5A and the voltage is 12V, 0.5
  3. Hero999

    opamp roll-off

    I've deleted my previous post, he hasn't logged on since so hopefully he hasn't seen it, unless he sneaked on as a guest.
  4. Hero999

    ec lab

    http://www.google.co.uk/search?client=opera&rls=en&q=PLL+frequency+multiplier&sourceid=opera&ie=utf-8&oe=utf-8 http://home1.gte.net/res0658s/fatman/4046pll.html http://www.cardinalxtal.com/docs/notes/cardinal_phase_lock_loop_basics.pdf...
  5. Hero999

    opamp roll-off

    Where did I say that? Post a quote? I wouldn't say that, I'd say that the 741 should be operated so it still has plenty of gain at the frequency you want to amplify  and that the output should be kept within the slew rate. Anyway I tried, maybe I shouldn't have bothered.
  6. Hero999

    opamp roll-off

    I'll have a go at explaining. The slew rate is the maximum rate of change in output voltage. Suppose slew rate is 1V/
  7. Hero999

    Class D audio amplifiers!

    There are probably cheaper and better MOSFETs around. Audioguru hasn't explained how he came to the conclusion about the power output. It's Ohm's law. The maximum peak voltage output of a half bridge driver, which is what you have, is always half the maximum voltage swing, which is always...
  8. Hero999

    Design new 0 to 30V power supply.

    That can't be right, Vref shouldn't change at all. U5 shouldn't be getting warm at all, R18 might get very slightly warm because it's dissipating just over 0.1W but it shouldn't be very hot, I doubt you'd notice it. I'm sure the circuit is right, it's the same as the datasheet...
  9. Hero999

    Design new 0 to 30V power supply.

    As I said before, that shouldn't make any difference to the current at which it starts to limit. R21 just changes the delay. There must be something else which is wrong.
  10. Hero999

    Class D audio amplifiers!

    Sorry but the circuit you posted will be no more efficient than a class AB amplifier and won't sound anywhere near as good.
  11. Hero999

    Design new 0 to 30V power supply.

    That's an easy mistake to make. Which resistor was it? I'm still questioning this because there are no 100k resistors apart from the pot's and replacing a 100k pot with 10k should have this effect. The only explanation is that you were intending to subsitute a value you couldn't get hold of...
  12. Hero999

    Design new 0 to 30V power supply.

    I'm still not sure if you know what I mean, sorry if you do I'm just boring you. I'm interested to see if the tap switching works. For output voltages under about 12V, M1 should be off, so the power being delivered to +V is coming from the centre tap (via D5): +V should measure about 21V, give...
  13. Hero999

    Design new 0 to 30V power supply.

    That won't work well with this circuit. Suppose you put the 1k pot. in series with the positive side of R21: altering the 1k pot will make a large difference when R21 is set to the high setting and not much difference when it's set near 0V. If you put the 1K in series with the negative side of...
  14. Hero999

    design an audio amplifier

    Why bother with a poll? The answer is yes but no. Yes, you can build an audio amplifier with an LM741 but no, it's not worth doing because it will sound horrible.
  15. Hero999

    Design new 0 to 30V power supply.

    Great, I'm really glad my design works. Thanks to all that helped me design it and you for building and testing it. That's to be expected. If you set the current limit to zero then the output voltage will drop to zero because it won't allow any current to flow and Ohm's law states that at zero...
  16. Hero999

    0-30V Stabilized Power Supply

    I like the way you've done the silk screen - I use the same method. :D I notice there's a track that doesn't go anywhere and another track is broken; is that deliberate or a mistake?
  17. Hero999

    Isolated ground planes on a MCU controlled high voltage IGBT

    What about using something like this? http://www.electro-tech-online.com/attachments/electronic-projects-design-ideas-reviews/39571d1267245370-series-connection-battery-cells-fets-.pdf You need to use two transistors, as it's DC, not AC, one will do. Of course you could replace the logic...
  18. Hero999

    Design new 0 to 30V power supply.

    I hope you're aware that your breadboard will not be able to handle more than 1A so you need to connect all the high current components with wire, off the breadboard.
  19. Hero999

    Design new 0 to 30V power supply.

    I don't think anyone has made it but I'm certainly interested if you make it. If you get it working and post some pictures I'll put them up on Silicon tronics if you like.
  20. Hero999

    ELECTRONIC FAUCET

    I think I know what you're saying a 'faucet' is US for tap? An electronic eye is something which detects the presence of your hands? The detcetor can be a PIR sensor, which detects the IR radiation emitted by your hands, as I said above, an IR beam which gets broken when it's obscured by your...
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