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Photo flasher circuit

  1. Oct 21, 2014 #1
    Hello everyone

    I'm new here, and currently trying to learn more about electronics. - Since my knowledge is very limited, I've decided to take apart some old devices from the garbage, and recently tried to understand a photo flash circuit from an old camera, and to trigger it with my own bench power supply. - But with no success yet.

    I tried to trace out all the components, and make a schematic (in DipTrace), just as an excercise. I'm sure that there are still plenty of errors in it! (E.g. the transformers and unidentifiable SMD parts etc. - The trigger coil seems to be connected to ground on both sides, but I'm not sure, since I wasn't able to see where its pins go...)



    Pin 1 is ground.
    Pin 2-4 seem to be for the status LEDs. I grounded pin 2/3.

    I don't know the required voltage and how to test things without damaging the circuit.

    I tried to apply voltage to the remaining pins (actually by trial and error) of maximum 6 volts (since the battery was about 6 volts). And I monitored the charge of the large photo capacitor (not on the picture)... - But it didn't charge at all yet.

    Pin 4 seems to be for the trigger, since it goes to the SCR (which is new to me).

    I'm basically lost, since I don't understand the circuit. - Search on the web didn't help much yet, since my circuit has multiple parts that I don't yet understand.

    I'm thankful for any advice!
    Last edited: Oct 21, 2014
  2. jcsd
  3. Oct 26, 2014 #2
    Thanks for the post! Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post?
  4. Oct 26, 2014 #3


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    I suspect you'd learn more, and more quickly, by buying one of the readily available breadboard kits that are for the purpose of learning the basics. That and a cheap multimeter and you'll learn a ton of stuff, and from the ground up.
  5. Oct 27, 2014 #4
    Thanks! - I didn't have the time yet to work on this since the post but I'd like to find another cam with a flash on in the electro garbage nearby soon to see a working circuit in action... So that it would also be possible to measure required voltages and monitor the behavior on the oscilloscope (I actually got from that thrash container as well recently :D ).

    And Greg, yes, I'll keep you up to date if I find out more about this. - The main issue is this "flyback transformer", need to learn more about coils, inductive loads, transformers, these are still quite tricky for me to understand... and to visualize mentally. How the magnetic field in a coil collapses and generates that required high voltage for the trigger.... Actually I'd like to build a stroboscope out of similar parts, which works in similar way like in the flasher above.
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