Found in 1968 Mullard documentation, this circuit uses period components. The transistors are matched pairs and the sensor is an Indian photocell of the time.
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...