Found in a 1968 EEE, this circuit accepts frequencies from 1 to 1000 Hz and control voltages from 0.1 to 15 V. The operational amplifier is from the era and can be replaced by modern equivalents.
If we modulate a beam of light from an LED, for example, we can receive this beam of light at a...
This circuit is from a publication of the 70s, but it can be easily assembled with the BC548. The...
In the circuit in the figure, when a pulse of light falls on the LDR, the circuit arms with the...