With this simple circuit it is possible to simulate a telephone line for carrying out repairs on telephone sets. The transformer must be 36 V and the diode can also be 1N4004.
This circuit can use both separate LEDs and a common cathode display when one segment indicates...
The circuit shown was found in the National Semiconductor Linear Applications Handbook of 1994. The...
Found elsewhere in this section, but from other sources, this circuit is from Motorola...