The transistors of this circuit found in a 1965 magazine can be the BC558 and the sensitive 12 V x 50 mA relay. The other components are common.
We found this chopper circuit in a 1967 publication. The transistors are of the time, and current...
This circuit was found in a 1977 Radio Handbook. The ports used are CMOS like 4001 and the...
Ohmite TGHD non Inductive High Power Resistors Available in SOT-227 enclosures, these Ohmite...