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.
We found this circuit of a transistor siren in a recent English publication. All components are still...
We obtained this circuit from the 1977 National Semiconductor FET Databook. The frequency depends only...
This circuit makes use of the LM11, 112 or 113 operatives and was found in a 1980s documentation. The...