This configuration is from the 70s, having been found in an American documentation. The transistors can be BC549 for Q1 and BC548 for Q2.
Suggested by National Semiconductor in documentation from the 90s, this circuit makes use of an...
This test for electrolytic capacitors was found in the October 1960 Radio Electronics magazine. Note...
This circuit was found in a May 1981 Radio Electronics magazine article. The circuit is offset...