With this circuit it is possible to receive and send audio signals simultaneously over the same telephone line. The circuit was found in an Elektor from the 90s. The power supply is symmetrical.
Found in National Semiconductor documentation from the 1980s, this circuit can be implemented with...
This circuit was found in a 1968 EEE. The circuit makes use of logic gates of the time and can be...
We found this circuit in a publication on operational amplifiers from 1978. The circuit is made...