We found this version of the automotive tachometer in a 1980s publication. Variations from other sources appear elsewhere in this section. The indicator is a 0 to 1 mA milliammeter.
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...