The circuit presented was suggested by Texas Instruments in an opto-electronics manual. The transistor can be the BC548 and the supply voltage depends on the application.
This circuit is intended to measure the power of a transmitter for the citizen's band (11 meters or...
This metronome can use either a high impedance phone or a crystal phone. You can use a small...
The circuit shown in the figure modulates a low power infrared LED with TTL signals. The circuit can...