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  1. Hero999

    Need a bit of help (power amplifier)

    It sounds reasonable to me considering what you've measured is the off-load voltage before all of the losses in the rectifier and driver transistors.
  2. Hero999

    Need a bit of help (power amplifier)

    Is 81VAC the voltage you've measured of the transformer? 115V into 8R will give a theoretical maximum output power of 827WRMS.  You've calculated the peak power which is double. In reality, the actual power output will be much lower as there will be losses in the rectifier, driver transistors...
  3. Hero999

    DIY anti-theft circuit with infrared version 2

    All right, I'll respond. Where's the code and a detailed write-up of the project? Your soldering is horrible, especially the two LEDs dangling off the end of the board. I notice you're using Q1's base current to drive another LED, is that to save power? What does D1 do? Finally why are you...
  4. Hero999

    where and why TTL logic is used

    It isn't used, not any more, far newer technologies have succeeded TTL which was very power hungry and exhibited poor performance.
  5. Hero999

    LC and Oscillators

    How can he provide such an in-depth answer without the schematic? That's impressive.   ::) What sort of LC oscillator are you talking about? There are many configurations. The only thing you hint at, is you're using a BJT. Here are some examples...
  6. Hero999

    Simulation of 12-Watt Amp Help

    LTSpice is one of the most popular simulators in hobbyist circles. It's a powerful SPICE simulator and you can easilly creat your own models from the datasheets.
  7. Hero999

    propblem with RS232 to RS485 Pleased help!

    None of your links work.
  8. Hero999

    DIY Lithium ion charger?

    http://www.batteryjunction.com/tlunlichfor1.html
  9. Hero999

    P-cad Dos Schematic Transfer Problem With Pdifout, software problem

    Try booting from a boot disk. Another option is to transfer your files to your newer PC and run the DOS program on that. You may need an emulator such as DOSBox or Virtual Box. Of course it could be the hard drive on your old 386 is packing up. Have you backed everything up? If not, you should...
  10. Hero999

    How to connect electronic electricity system?

    Yes I know you already have all of the components. I meant, how much are you willing to pay for someone to design the schematic and write all of the code for you? Doing what you require would be quite time consuming. How much is someone's time worth to you?
  11. Hero999

    How to connect electronic electricity system?

    How much are you willing to pay for someone to design the whole system for you?
  12. Hero999

    New electronics hobbyist looking for good projects to start on!

    Maybe the first thing you should learn is that RadioShack is a poor place to buy electronic components. It's much better to look online, most people here buy from: Digikey, Farnell and RS Components because they stock a greater range, at more reasonable prices. RadioShack have a limited...
  13. Hero999

    Need portable power supply for diesel glow plugs

    What's the Ah rating of the batteries, at the current drawn by the glow plugs? You do the calculations.
  14. Hero999

    Need portable power supply for diesel glow plugs

    You need batteries with a high enough energy density. Reducing the voltage will do nothing, read up on Ohm's law, for a given amount of power (in this case heat), the current will need to increase proportionally, if the voltage is lowered. In your case, each glow plug requires 120W and you want...
  15. Hero999

    Testing a capacitor in curcuit w/ analog meter?

    Simply short circuiting a capacitor is a bad idea because the current will be very high so could weld the wire to its leads. It's much better practise to discharge it using a resistor to limit the current to under 10A. A word of warning: obviously be careful around large capacitors charged to...
  16. Hero999

    Simulation of 12-Watt Amp Help

    I wouldn't show a student the right way. Believe it or not, that wouldn't be helping them at all in the long run. It may help them pass the assignment but it wouldn't help them with the exam or when they get a job and have to do it for real. I'd help the student by giving hints about what...
  17. Hero999

    Eletronic stethoscope but different intent!

    Wrong prefix again, 79.9MV is 7990 000V, 79.9mV is only 0.079V http://en.wikipedia.org/wiki/Metric_prefix An  LED needs at least 1.8V to work. My guess is the actual peak voltage is more like 3V but it's so brief your meter doesn't have time to respond to it. If you connected it t an...
  18. Hero999

    LC and Oscillators

    You forgot the schematic.
  19. Hero999

    Eletronic stethoscope but different intent!

    I know it can pick up engine sounds. My concern is that the flashing LED part may not work as there are many harmonics given off by the engine. If you just want to listen, then fine but don't expect it to be able to flash the LED every time the injector fires. Fuel injectors are powered off 12V...
  20. Hero999

    Eletronic stethoscope but different intent!

    This circuit won't differentiate between one sound and another, that's much more difficult to do. It sounds like you're doing it the hard way. Why not connect an LED and resistor across the injector coil, or if you don't want to make physical connection, use a coil to detect the injector coil's...
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