This circuit was obtained from an American documentation from 1968. The current depends on the operational, observing that the circuit uses a symmetrical power supply.
In this circuit the CA3140, an operational amplifier, is used as a comparator with the zener diode...
The voltage gain of this amplifier is 10 times. This gain is given by the relationship of values...
This circuit is intended for the use as modulated light signals from digital sources. The circuit...