Simple Pulse Generator by IC 555 Timer. This is a simple pulse generator circuit with IC 555 timer. Use for digital Logic circuit. IC 555 use voltage supply 5V to 15V. The output’s frequency is control by R1. Detail more, Please read in this image circuit 4017 Led Pattern-Flasher
Avalanche Pulse Generator Build Using 2N3904 and Avalanche Pulse Generator web page offer plans for a The circuit works so that R2, C1 along with the NPN transistor form a relaxation oscillator.