This circuit with the ULN3784B appeared in the October 1984 issue of Radio Electronics magazine. It can typically be powered from 9 to 24 V.
This single transistor radio without a power supply was found in documentation from the 1960s. The...
This circuit is from a 1982 documentation. Here we have an adaptation of the circuit already...
This circuit is suggested by Motorola, using a 4N26 type coupler and an MC1733 type operative. However,...