Battery Voltage Indicator (CB15369E)

This circuit was found in the Intersil Databook. The integrated circuit used is uncommon today. R2 sets the trigger voltage according to the battery.

Increasing the voltage of a fixed regulator (CB8476E)
Found in a 90s Electronic Design, this suggestion to have a higher voltage in a fixed regulator...
VCO operational (CB9436E)
Found in Fairchild documentation from the 90s, this circuit generates signals with the...
PWM with 555 (CB11853E)
This circuit is intended for PWM speed control of a motor up to 500mA, using integrated circuit 555....