In this circuit, the integrated amplifier used is uncommon today. The circuit is from an American documentation from the 70's making use of a power transistor for output. A TIP32 can be used.
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...