Led Flasher LOW VOLT

The following schematic is of the discrete component replacement for the LM3909.
The values of the components were chosen to match those in the integrated circuit however resistor R5 is a guesstimate fit as the Q2 portion of the circuit as Q2 in the integrated circuit is a “current mirror” which is a type of current regulator.
The Q2 portion of the circuit could not easily be duplicated using individual transistors but could be replaced with dedicated current mirror device.

Discrete Component LM3909 Circuit Notes The values of the resistors in the discrete circuit can be adjusted to change various parameters of the circuit. (There is plenty of room to experiment with this circuit.)
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This circuit has not been tested in any other mode other than that shown in the above schematic. There is no apparent reason that it shouldn’t work in the other circuits shown on the LM3909 data sheet if the zener diode D1 is replaced.

Source: http://home.cogeco.ca/~rpaisley4/LM3909.html

This entry was posted on Thursday, June 28th, 2007 at 1:29 am and is filed under LED Flasher.

Circuit diagrams and schematics - Electronic projects

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