This is a channel of a stereo amplifier and small power with the LM386 suggested by the Radio Electronics Experimenters in the 1981 edition. The power of a few Watts.
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...