Astable Multivibrator 1:

Astable Multivibrator 2:

CMOS Toggle Flip Flop With Relay(CD4013):

Discrete BiStable Flip Flop:

Discrete Set / Reset Flip Flop:

Fast Rise time Multivibrator:

Flip-Flop Flashers, Buzzers, Etc.:

Gated Oscillator Emulates a Flip Flop: 03/16/95 EDN-Design Ideas 

Independently Vary a Multivibrator's Duty Cycle and Frequency : 10/28/02 Electronic Design - Ideas for Design  / When testing the response of many pulse-width-modulated (PWM) systems, there's a need to independently vary a multivibrator's frequency and duty cycle. Such systems include dc motors, ultrasonic hydrophones, and piezo-ceramic transducers. The ...  

Mains Operated Christmas Star:

Monostable Multivibrator:

Soft On / Off Switch: Modern electronic equipment incorporates "push-to-on-push-to-off" switches that do not make the clicking noise as with old equipment. An example of this is the power button on an ATX computer cabinet. Here is a circuit that does the same. It can be used to turn on/off any electronic/electrical equipment that operates on any range of voltages. FAIR WARNING -- THIS SITE HAS ANNOYING POP UP ADS.

Stable Multivibrator (IC):

Stable Multivibrator (Transistor):