LED flasher from a 1.5 volt battery

[k7elp60]

The attached circuit will flash Red,Yellow, and Green LED's from a 1.5 volt battery such as AAA,AA,C, and D cells. Q1 and Q2 is a multivibrator. Q3 and Q4 is a voltage pump. The no-load voltage on the + side of the 100uF capacitor to ground is about 2.7 volts. This circuit approaches the obsolete LM3909. If the 10uF capacitors in the multivibrator are replaced by .01uF the whole circuit becomes a voltage pump and the LED will stay on steady.
I thought I would share this circuit with the members of the forum.

 

[stevez]

I recall that one IC (maybe the 3909) provided a very short pulse at a higher voltage to create a more attention getting blink to a flashing LED. Does this circuit do that? Regardless, thanks for sharing.