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 was found in a Mullard transistor manual from 1960. Note the symmetrical power...
This amplifier step with a transistor has an input impedance of 100k to 10 M. The transistor can be any...
I found this little signaling transmitter in old American documentation. The circuit has a good...