This long interval timer was found in the September 1976 issue of Radio Electronics magazine. The output can be used to control a relay. The circuit achieves timings of up to 14 hours.
This is the circuit for the HM-10ª, an instrument sold by Heathkit. The circuit is from a Radio...
This circuit indicates when the monitored voltage drops below the value determined by the divider...
This circuit, from a 1975 Motorola manual, uses a power Darlington transistor of the time. We can...