Found in a 90s Popular Electronics, this circuit can power a miniature railroad with voltages of 15 V and currents up to 1 A. The circuit has soft start effects.
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....