Where can I find a circuit that will pulse an array of 36 led lights at 14

  • Thread starter Thread starter c_dyer01905
  • Start date Start date
set up a pair of 555s (see reference), one as a oscillator at 14 Hz, the other for the pulse width you want for the flash.

use a driver transistor to drive the LED circuits

You need to look up the Vf and I max of the LEDs and decide how many you can put in series for 12 volts, and what resistor to use. Assuming 3.2 volts typical Vf at 20 mA (numbers I made up), then you can put 3 in series for a total of 9.6 volts and 2.4 volts across the resistor, which is 2.4/20 = 120 ohms. (2.4 volts is a bit marginal, you may want to put only 2 in series)

So you will have 12 strings of 3 each, the 12 strings in parallel, so you need 20*12= 240mA of drive.

So the driver can be a 2N2904, E to +12, C to the strings. B to the 555 output via a 1k resistor.

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