Have you ever needed to power a 12-volt relay in a circuit but only had 6 or 9 volts available? This simple circuit will solve that problem. It allows 12-volt relays to be operated from 6 or 9 volts, ...

There are several applications at home or industry for long delay timers (ON or OFF delay). Time delays on the order of seconds can be generated using 555 timer circuits, provided the timing capacitor ...