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  1. Arouse1973

    Will my circuit work? (trying to make a who pressed first quiz buzzer)

    Hi John Technically only one would need to be reset at a time, but I am not sure how Robert wants to do it. He may want each person to be able to reset their own LED themselves? Thanks Adam
  2. Arouse1973

    Will my circuit work? (trying to make a who pressed first quiz buzzer)

    Here is my initial version of the 555 timer part. Hope this helps. See if you can workout where to take the hold off from for the other persons button. Adam
  3. Arouse1973

    Anybody know where I can get a collection of electrical symbols clip art

    Robert you have opened a new post with the same circuit info. Just keep one otherwise it might confuse people. We will answer any questions related to this even questions about the drawing of the circuit. Choose one to carry on with. Any related info from the other can be merged by one of the...
  4. Arouse1973

    Will my circuit work? (trying to make a who pressed first quiz buzzer)

    OK I have never used a 555 timer, so I will have to have a look into how they work. But initially I would say why are you using a 555 timer, do you want it to latch or just stay on while the person is pressing the button? Also you need some LED current limiting resistors and two more base...
  5. Arouse1973

    Anybody know where I can get a collection of electrical symbols clip art

    Ahh I was mistaken. I have the student addition of Tina which does flash the LEDs. To see the output you can connect an Oscilloscope to the circuit using one of the meters to the circuit or use the transient analysis option. Tell me what you want to draw and I can help. Adam
  6. Arouse1973

    Anybody know where I can get a collection of electrical symbols clip art

    It should flash on it's own. Adam
  7. Arouse1973

    OpAmp oscillator circuit

    Yep correct,cheers Hop. The circuit I drew what the correct way to draw his original oscillator circuit. Thanks Adam
  8. Arouse1973

    Rest in Peace, Kris

    Kris You have been an inspiration to many of us, I enjoyed reading many of your detailed posts which you used to write with such ease. I remember saying to you bloody hell Kris, that would have taken me all weekend to write that much. It took you half an hour. You must have had smoke coming from...
  9. Arouse1973

    OpAmp oscillator circuit

    PWM controller. The following stage samples the RC time constant triangle ish wave, so you can vary the pulse width. I guess that's what he is doing? Adam
  10. Arouse1973

    Anybody know where I can get a collection of electrical symbols clip art

    Never used it. But I would stick to one package for the moment. If you want to do PCBs later on then DIP TRACE is another good package. Adam
  11. Arouse1973

    Anybody know where I can get a collection of electrical symbols clip art

    Tina Ti is what you need. It's free and very easy to use. Download it and give me a shout if you have any issues. http://www.ti.com/tool/tina-ti Adam
  12. Arouse1973

    OpAmp oscillator circuit

    Hello This is how I think your oscillator circuit should look, operating from a single supply. I assume this is some kind of PWM circuit driver? Thanks Adam
  13. Arouse1973

    Anybody know where I can get a collection of electrical symbols clip art

    Hi Bob Is this to draw circuit diagrams with? If so what are you having trouble with? Adam
  14. Arouse1973

    Hello from Germany

    Hello Jurgen Welcome to EP Adam
  15. Arouse1973

    Stage Line 500W amp repair project

    Hello I am a bit concerned about Kris also. I have messaged him but he has not responded, I am trying to find out if he is ok. Adam
  16. Arouse1973

    Charger ?

    Hi Al Did you get this from someone that used to work in the military? Adam
  17. Arouse1973

    Transistor switching

    I don't quite understand why the keyboard is only outputting such a small voltage. How are you measuring this? The information I have found regarding the VCO output says it's a square wave, you are not going to be able to transmit very far if at all with this without some kind of resonant...
  18. Arouse1973

    Help calculating the resistors

    Or the LEDs are reversed :)
  19. Arouse1973

    Transistor switching

    Is this a PC keyboard? Can you link to the data sheet for both the transmitter and the receiver modules you are using. The data from the keyboard will also be inverted, is this an issue? Adam
  20. Arouse1973

    BJT Transistors

    Hello Think about what voltage you have across the resistor Rref. You know the current you need in Rref to ensure the other transistor matches this. Can you work this out now? Adam
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