This amplifier, whose mounting on a printed circuit board was described in Radio Electronics of October 1960, has 35 W of power. The power supply uses a transformer and a set of 5 tubes.
The figure shows three circuits for using headphones in amplifiers with speakers that do not have...
In this charger, the charging current is basically limited by the LEDs. The transformer is a low...
This configuration is from an old integrated circuit manual. The circuit can be applied to modern...