The time of this timer depends on C1. The circuit was found in the July 1994 Electronics Now magazine. The supply voltage depends on the relay and can go up to 12 V.
This circuit was obtained from a manual of the integrated circuit itself, but can be applied to...
We found this circuit in an 80's Radio Shack publication. The circuit uses a company buzzer, but...
August 2017 - Mouser Electronics is already stocked with Silicon Labs' I2C Si705x A10 interface...