Adjustable reference (CB21539E)

This circuit was obtained from an old American publication. The uA702 is a differential amplifier and the diode is a zener.

Delayed relay 4001 (CB24349E)
This circuit activates a relay after a time given by C1 and R1. The circuit is from a Radio...
Transistor Monostable (CB18232E)
This circuit can be used as a control shield for microcontrollers of all types. The supply is made...
Microphone Operational Amplifier (CB11590E)
In this circuit, D.A. which is actually O. A. of an operational amplifier, which can be any type...