This 10-minute timer was found in the July 1994 Radio Electronics magazine. The relay must be sensitive to the supply voltage used. The capacitors determine time ranges.
This simple circuit has good gain and can be implemented with any general-purpose transistor. The...
This circuit has a power stage with transistors that allows to obtain a current greater than that...
We found this circuit in Motorola's Linear Databook in 1990. The component used is not common today....