The integrated circuit used is uncommon today. The circuit was obtained in the Philips integrated circuits manual of 1990. The reference voltage-range is from 0.5 to 9.0 V.
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...