This circuit allows you to vary the duty cycle without changing the frequency. An interesting application for PWM controls. The circuit is from a Radio Electronics magazine from July 1985.
This Nixie pipe circuit was found in 1965 documentation. Note the high supply voltage. Appropriate...
This circuit is from a 1976 publication, but it can be assembled with modern components. For the...
Found in Popular Electronics from the 90's, this circuit consists of an audio oscillator for Morse...