This circuit supplies a voltage of 42 V, plus a symmetrical voltage of 12 V with 1 A. The voltage regulators must be mounted on heat sinks. The transformer is 35 + 35 V with 3 A.
The transistors are 2N918, 2N3464 and other RF equivalents of the time for Q1. For Q2, 2N3399, 2N2894...
This circuit, which can be used as a shield, was found in a 90s Electronic Design. The circuit...
This interesting intercom circuit was obtained from an Argentine publication from the 1970s....