1-minute delay (CB21408E)

This circuit with PUT is from a 1967 General Electric manual. The relay must have voltage according to the supply.

Photo controlled triac (CB8312E)
This circuit was found in an Electronics World of 1968. It can be applied to any modern triac and...
Listening Monitor and 27 MHz Field Meter (CB19602E)
This circuit is from a documentation from the 70s. The transistors are types of germanium of the...
Audio Preamplifier (CB6479E)
Obtained from a 1996 documentation, this circuit uses common components and has a voltage gain of 200...