This circuit makes use of components from the time it was published. The TCA151 is not a common component today. The circuit generates 10 to 10 kHz signals.
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...