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.
The voltage gain of the circuit shown in the figure is 10 times. This gain is given by the ratio...
This circuit, from an old Argentine publication, uses a slightly different symbology than we are...
In this circuit we have two oscillators, one controlling the other, using the 4 NAND gates of the...