Found in a Popular Electronics from the 9s, this circuit has output for RS-232 interfaces and current input. The power supply must be symmetrical.
This interesting circuit found in American documentation generates a busy signal, without you...
In this circuit R1 is 56 ohm and R2 is 220 ohm for the 110 V network. SCRs are according to the...
We found this circuit in a 70s EDN. The circuit makes use of operational of the time. | Clique na...