This circuit is from an Electronics World of 1968. The transistors are of the time and the power is supplied with a voltage of 40 V. The circuit is high fidelity.
This circuit, with printed circuit board included, is from a Radio Electronics magazine from July...
In the figure we show how to excite a CMOS port by interrupting light on a Darlington...
We found this circuit in an old documentation, but it uses components that are still common in our...