This buzzer trigger can be used for small alarms. We find it in an 80’s American documentation. The supply can be done with voltages from 3 to 18 V.
This frequency divider by 10 uses discrete components only. Modern equivalent components can be used as...
Found in an article in the August 1971 Radio Electronics magazine, this circuit supports sensitive...
We found this circuit in a 1972 RCA technical documentation. The comparator can be any type and C1...