This circuit from an old documentation includes the power supply for the 117 V power grid. It can be adapted to other networks by changing the 10k resistors.
Using bipolar, FETs and unijunction this long-lasting timer can reach 10 hours with good quality...
The configuration shown is from the National Semiconductor Linear Applications Handbook. The...
This shield circuit uses a common CMOS port. The voltage depends on the interfaced logic. The...