Capacitance multiplier (CB7803E)

We found this circuit in an old Popular Electronics. The circuit can be applied to other operational amplifiers.

High Quality Radio (CB23626E)
This 10-transistor radio was found in Radio Electronics magazine from December 1964. The...
555 Voltage Controlled Oscillator (CB19028E)
In the figure we show how to implement a voltage-controlled oscillator. The circuit is from Texas...
Wien II Bridge Oscillator (CB4924E)
This circuit generates signals from 0.01 Hz to 10 kHz, but uses unusual components today. The...