This circuit was obtained in an American documentation from the 80's. The transistors can be equivalent to those indicated and the crystal can reach a few tens of megahertz.
This circuit can be used to test zener diodes up to 25 V using a standard multimeter. The voltage...
This TTL traffic light circuit was found in an English magazine from 1977. The magazine no longer...
This circuit is from National Semiconductor documentation. The operational amplifier is of the...