The expansion rate of this circuit is determined by R. The circuit can use any operational amplifier and the power supply must be symmetrical. Resistor R must be less than 10k.
This circuit was found in an American publication from the 60's. The transistor is from that...
This circuit was originally found in Radio Electronics magazine, enabling the transmission of...
This circuit with transistors of the time was found in the magazine Radio Electroinics of June of...