This circuit was found in the Linear Applications Handbook of the National Semiconductor of 1994. Some of the components used are not easy to obtain, but equivalents can be used.
The purpose of the circuit shown in the figure is to open and close the contacts of a relay...
This timer uses common components today. It activates a relay after intervals that can be adjusted up...
Supplied in a 2005 Linear Technology Application Manual, this circuit monitors the charge and...