Using 3 NPN transistors, 3 capacitors to make and control LED blinking

This post is about making and controlling LED blinking. The schematic and demo video, as per below.

The battery source is 9V.

To reiterate a few points which is stated in the image above:

  • The original value of C3 is 220uF. I change it to 1uF. Circuit design taken from ‘Make: Electronics 2nd edition’. A fantastic book for electronics hobbyist.
  • Reduce C1 and C2 value to increase blinking rate.
  • Increase C1 and C2 values to reduce blinking rate.
  • Lopsided C1 and C2 values (C1>C2 or C2>C1) to create different rate for ‘On’ and ‘Off’.

A short demo video: