integrity of this circuit

Discussion in 'General Electronics Chat' started by markosillypig, Mar 4, 2012.

  1. markosillypig

    Thread Starter Active Member

    Jul 21, 2008
    184
    0
    hi all i got this circuit diagram off the net but i dont belive it to be correct can any one just have a quick look and tell be if what i have changed is correct and if the final circuit is ok

    i intend on removing the led's and replacing it with a 1 amp transistor any recomendations on what to use as it will be switching on 1 amp of led strips?
    thanks
    marko
     
  2. mlog

    Member

    Feb 11, 2012
    276
    36
    First, I would suggest you get a data sheet for the 555 timer so that you can understand how it works. Basically the output (pin 3) is high while the capacitor is charging and low otherwise.

    With the present values, the output will go high for ~4.3 seconds and low for ~0.4 seconds. Duty cycle (time high/time low) is ~11 and frequency is ~0.21 Hz. So in effect, every 4.7 seconds, the output is high (LEDs are on) for ~92% of the time and low for ~8% of the time.

    The output is TTL compatible, so that should give you an idea of the drive characteristics.
     
    Last edited: Mar 4, 2012
  3. markosillypig

    Thread Starter Active Member

    Jul 21, 2008
    184
    0
    would a 2n7000 be ok ? i have worked out i could go as low 400mw
    thanks
     
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