This circuit was found in a 80's Popular Electronics. The sensor can be any phototransistor. The circuit is indicated for an audio link modulated in pulses.
We found this circuit in a 1997 documentation. Its purpose is to fan an inverter for fluorescent lamp...
We find this circuit in a 1994 technical documentation. The circuit has a 12 V input and a 33 V...
In the figure we show how two diodes can be used to simulate the center tap of a push-pull driver step....