Diode Tester (CB22137E)

This diode tester was found in an English publication from the 1980s. Transistors are general-purpose types of the time.

Photoelectric switch (CB8252E)
Found in a 1970s RCA documentation, this circuit uses a relay to control external loads. R1 is 150...
Operational RC Oscillator (CB19348E)
The frequency of this oscillator depends on the capacitors and typical values for the resistors are 10...
Voltage Comparator LM3900 (CB5048E)
The connection of high-value input resistors causes the circuit to behave like a conventional...