Astable 555 (CB21101E)

This 50% duty cycle configuration was found in a Popular Electronics from the 1990s. The operating frequency is given by C1.

4040 Oscillator (CB14984E)
This traditional rectangular oscillator configuration generates signals up to a few megahertz...
Music Generator (CB9882E)
This circuit is just a curiosity found in a 1990 documentation, since the integrated circuit used...
Voltage Drop Alarm (CB1530E)
This circuit goes into operation producing a sound on a small speaker when the supply voltage...