Radio with amplifier (CB20486E)

We found this circuit in a publication of 1991. The audio amplifier is an operational that admits equivalent.

Pulses for data systems (CB8867E)
This circuit was found in a 1966’s American publication. What it does is to receive a pulse and...
Simple ohmmeter (CB4152E)
The idea of this circuit is a resistance meter or continuity test with a common microammeter or...
Capacitance multiplier (CB20746E)
Modern operations can be used in this circuit that multiplies a capacitance of 10,000 uF for a...