Integrator with bias compensation (CB20991E)

This circuit was found in a Popular Electronics from the 90's. It can be implemented with equivalent operational amplifiers.

Special LED Effect with the 4017 (CB12137E)
This special effect circuit with LEDs using the 4017 was obtained in a 1982 publication. LEDs are...
Telephone amplifier (CB9405E)
Found in a 1967 Electronics World, this circuit uses unusual components today. The transformer has a high...
Operational Oscillator (CB15447E)
In the figure we have the basic configuration of a rectangular oscillator using an operational amplifier...