This circuit uses a dual-gate MOSFET, a rare component today. We found it in American documentation from the 1980s. The rest of the components are common.
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...