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  1. Hero999

    Ordinary carbon paper instead of TRF Green

    I've never heard of it so I Googled it. http://www.pulsarprofx.com/pcbfx/main_site/pages/products/toner_foils/toner_foils.html Some people I've met on other forums swear by expensive proprietor papers like this but I wouldn't waste my money on it. I've has perfectly acceptable results using...
  2. Hero999

    Variable supply using LM317 with 32Vrms transformer rating

    Yes get the 60V version, you've no chance of doing it with the normal LM317. Does the 32V winding have any taps? If you add a relay you can reduce the power dissipation at lower voltage settings. The LM317 can't got below 1.25, without a negative supply and additional components. The current...
  3. Hero999

    Power Amplifier for Guitar

    There's a good article on impedance on Wikipedia. Oh I see, you think simply putting a power transistor into a low power pre-amplifier design and increasing the voltage will make a power amplifier? Well no it doesn't work like that, you need a class A-B design for a power amplifier which is a...
  4. Hero999

    Power Supply Disc Capacitor Rating (Mark CN2 )

    PCBs very rarely have component values printed on them,. It's just a reference to the schematic and you need to have this to get the correct value.
  5. Hero999

    Power Supply Disc Capacitor Rating (Mark CN2 )

    I removed your other thread: don't make duplicate threads, read the post linked to below: http://www.electronics-lab.com/forum/index.php?topic=19562.0 CN2 only means something to the capacitor manufacturer. Are there any other markings? The value marking normally if normally in pF and...
  6. Hero999

    Power Amplifier for Guitar

    You'll get more help if you post the schematic. How much power do you need? Is this going to be powered from the mains or a large battery? Why not use an IC such as the TDA2005? http://kitsrus.com/pdf/tda2005.pdf For the input stage you could use an op-amp such as the TL072.
  7. Hero999

    Switched capacitor voltage boosters

    Using Schottky diodes would reduce the voltage drop to 0.3V per diode. CMOS gates have a high output impedance so you can't expect great efficiency. If you use the 74C14 you can make an oscillator using a single gate and use a fizv stage booster.
  8. Hero999

    audio amplifiers

    I hated audiofools. I remember someone on another forum thinking his old crackly vinyl record player sounds better than a modern CD player which I can just about take but he refuses to accept a FLAC codec with a ridiculous 24-bit 192kHz sample rate is better.
  9. Hero999

    problem gain 741

    The LM74 needs a dual supply for this circuit to work properly. Even if the 741 is correctly powered, the demonstration won't work as expected because the simulation program's models are probably not very accurate: The 555's output saturates at 1.4V so with a 9V supply you can expect a 7.8V...
  10. Hero999

    audio amplifiers

    How much power would a class A 65W amplifier use? >200W which is enough to fry an egg on.
  11. Hero999

    newbi to transistor numbers and letters after

    The parts are electrically identical, PbF just means lead free.
  12. Hero999

    New to electronics

    I posted a link to the datasheet in my previous post. You won't be able to buy it because it's obsolete. Nowadays microcontrollers are used to make alarm clocks because they are cheap, flexable and require less external components.
  13. Hero999

    0-30V Stabilized Power Supply

    A transformer either an inductor or an autotransformer. You need a transformer with at least two windings (primary and secondary) for this project. Never use an autotransformer because it doesn't provide isolation form the mains.
  14. Hero999

    New to electronics

    What does it do? I couldn't find anything for MK5025ON but MK50250N  came up with plenty of results. http://electronballet.com/Datasheets/NIXIE/MK50250_53_54.pdf
  15. Hero999

    UV exposure box

    Yes, that should be fine.
  16. Hero999

    New to electronics

    Please post a schematic. The transistors look fairly generic and easy to substitute. I think MK5025ON is a mistake, you probably mean the MK50250N, yes it's easier to get zero confused with the letter O. I hazard a guess the project is an old design and there are more cost effective...
  17. Hero999

    Using circuit power supply to power relay load ...

    Oh sorry, I missed the link. Yes either of those options will work.
  18. Hero999

    help ...to control pulse width of a -15vdc pulse train

    Whoops I got the VDD and VSS the wrong way round. VDD = 0V and VSS = -15V, I've edited the schematic.
  19. Hero999

    Using circuit power supply to power relay load ...

    Yes  don't see why not, although it's difficult to really know without a schematic.
  20. Hero999

    help ...to control pulse width of a -15vdc pulse train

    It will work but you'll need to make some modifications to the 555 circuit: The input pulse is longer than the output pulse so you'll need to AC couple the input to the source otherwise the output will remain high after the delay has finished. The output needs to be inverted. Remember the 555...
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