The resistors R1 and R2 consist of 8 220 ohms x 2 W resistors connected in parallel. The dissipation must be higher for high transmitter power. The indicator can be the multimeter.
This circuit can be used to receive signals from CB18636E and other modulated light transmitters in this...
Due to its low working voltage, this circuit of an old EDN can be associated with a...
We found this circuit in a 1983 English magazine, but it can be easily assembled with the BC548...