This reinforcing stages from a 1960s documentation. No information is given about the transformer and the transistor admits equivalents.
If you have a common analog multimeter, you can increase its input resistance in the measurement of...
Found in a 1967 RCA manual, this circuit uses components from the era that can be replaced by modern...
August 2017 - Texas Instruments' new integrated circuit BQ25872, a 7-A keyed battery charger with...