This circuit drives a load with a delay given by the RC timing components. The circuit is from 1970s documentation. The diode is a general-purpose type.
This circuit was obtained in an old documentation, but it is still current by the used components....
This circuit makes use of a transconductance operational amplifier. It generates signals with TTL...
This circuit is from a 90s Popular Electronics. The transistors are of general use and the buzzer...