explanation of circuit diagram

Discussion in 'General Electronics Chat' started by falade47, Aug 8, 2017.

  1. falade47

    Thread Starter Member

    Jan 24, 2017
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    Please can I get dick capel or anyone to explain how this circuit works..i tried using the component specified on the diagram and it worked as stated..so i tried to see if I could achieve a frequency of 0.25Hz..so I used a higher capacitance of 1300uf, it took a while before the led came on (I suspected the capacitor was charging up) and then it started to oscillate at almost same frequency with the latter
     
  2. Jony130

    AAC Fanatic!

    Feb 17, 2009
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  3. falade47

    Thread Starter Member

    Jan 24, 2017
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    Can it be used to drive an external circuit circuit and be able to generate a frequency of 100hz
     
  4. DickCappels

    Moderator

    Aug 21, 2008
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    I cannot explain why making the capacitor 4x as large did not make the oscillation 1/4 as fast. The first flash will take longer than the period between subsequent flashes because the first flash starts with zero volts across the capacitor and it has to charge all the way up to the avalanche voltage before the flash occurs. Flashes only partially discharged the capacitor so it can charge back up to the avalanche voltage more quickly on flashes subsequent to the first flash..

    Should be no problem to get 100 Hz, but raising the frequency will result in dimmer flashes because unless you use more complex circuitry the capacitor will get smaller, thus making less energy available for each flash.

    Connecting it to an external device -one person connected a dynamic speaker in series with the LED and made a metronome.
     
  5. falade47

    Thread Starter Member

    Jan 24, 2017
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    Can I use this as a frequency generator to drive mosfet for a small inverter?
     
  6. DickCappels

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    Aug 21, 2008
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    You can but it probably would not work well. For one thing, the duty cycle is difficult to vary. There are many better methods of driving MOSFET gates.
     
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