Crystal oscillator (CB9504E)

This circuit was found in a 90s Popular Electronics. It can generate signals from 3 to 10 MHz.

Voltage Sensor 4069 (CB25881E)
Other CMOS gates can be used in this sensor, which we found in the July 1995 Electronic Now...
Electronic Pendulum (CB5022E)
This circuit is from the American magazine that no longer exists Science & Electronics,...
200 Hz to 2 kHz VCO (CB25247E)
Using the 4046 PLL we found this circuit in the December 1989 Radio Electronics. The circuit...