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  1. BobK

    Sawtooth generator with PNP transistor

    Duplicate.
  2. BobK

    Sawtooth generator with PNP transistor

    Your circuit is basically an emitter follower. That means the voltage at the emitter will follow the voltage at the base + about 0.6V. The 1M resistor biases the transistor into the linear region. If you take out the input pulse, I get the emitter at 3.4V. Now you couple a 1V pulse to the...
  3. BobK

    Woo-Woo Why are there countless attempts to make magnets power generators..

    So, basically, you went off and "studied" this for a year, and you learned nothing. What you put into the car is not your physical effort, it is the fuel. And you do not get out more energy than was contained in the fuel. A magnet does contain a very small amount of energy in the...
  4. BobK

    old extension amp to guitar amp

    Have you verified that the amp works at all? Will you get sound out if you connnect the amp's input to the out of an MP3 or CD player? It is likely designed for that kind of a level in. A guitar puts out a much lower signal, more like a microphone.
  5. BobK

    Need help with project

    Welcome! So you have an input, and you expect 4 pulses of unknown timing or duration. And you want them to be routed to 4 different outputs. Must the output pulses be of the same duration? How much delay can be tolerated? How about the magnitude, is it constant or variable? What are the...
  6. BobK

    Woo-Woo Why are there countless attempts to make magnets power generators..

    You are reminding me? Oy vey! It is violation of conservation of energy. There are no loopholes. If there were, the universe would be an entirely different place. Bob
  7. BobK

    help choosing right mosfet

    Cool! I could use one of these. Bob
  8. BobK

    Woo-Woo Why are there countless attempts to make magnets power generators..

    I meant exactly what I said. When the boulders, or the magnets are together they have no potential energy. They cannot do any more work. They only have potential energy when you seperate them. And they they have only the same energy that it took to seperate them. There is not energy in the...
  9. BobK

    help choosing right mosfet

    So you are going to squirt someone as they pass the sensor? Bob
  10. BobK

    Non-inverting amplifier

    If the input is always a square wave of 10V you could put it through a CMOS inverter powered by 12V to get a 12V square wave. This, however, implies that you will not be drawing much current from it. What is it driving? How much current is required. If more current is required, two discrete...
  11. BobK

    old extension amp to guitar amp

    Personally, I would replace the amp with something for a few bucks off Ebay. Edited. If you insist on using this amp, you probabably need only to add a preamp. Google "guitar preamp" for ideas. Bob
  12. BobK

    4017 count to 20

    Please explain exactly what you are trying to accomplish. You posts scream that you are making something more difficult than it is. Bob
  13. BobK

    Woo-Woo Why are there countless attempts to make magnets power generators..

    A magnet can do work in the same sense that a rock can do work, or water can do work. The energy is not in the magnet or the rock or the water, it is in it's releationship to other objects. A magnet in a magnetic field is no more of a mystery than a rock or bucket of water in a gravitational...
  14. BobK

    Woo-Woo Why are there countless attempts to make magnets power generators..

    Energy is the ability to do work. Work is force * distance. Bob
  15. BobK

    Looking for oscillator and frequency divider schematics

    I think a Schmitt trigger oscillator built with discrete components would work. The feedback resistor would set the frequency. You could even probably use a control voltage through another resistor to vary it. Edited: Welcome to the forum! Bob
  16. BobK

    Circuit project - HELP - LED display, solenoid, Pic18F452

    PORTD = 0xFF; Bob
  17. BobK

    Limited Resistance Range on 500ohm Pot

    Yes, I checked the specs and it does seem to be 6mA. If that is the case, a 9V would be fine to run it. Bob
  18. BobK

    220v LED DIMMER??

    He did show it in post 26. Bob
  19. BobK

    Looking for a circuit design

    PWM can be used to produce an analog voltage out of a micro controller, giving you a DAC capability. You do this by running it through a low-pass filter. You could use this analog voltage to place the transistor in the linear region. However, it would be subject to thermal runaway, so you...
  20. BobK

    Circuit project - HELP - LED display, solenoid, Pic18F452

    PORTD = 0 ^ 0xFF Means the the programmer did not know what he was doing. Bob
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