This circuit was found in a 1967 General Electric documentation. The components are from that time. The load depends on the SCRs used.
An inproved version of the circuit CIR129E is shown here. The resistorR1 must be at least 5 times...
We found this circuit in an old documentation. It can be elaborated based on modern components. The...
In this circuit of a 1956 publication, the handset must be high-impedance magnetic and L1 has 200...