This circuit provides 2.5 W of power with 6 V supply and 4-ohm speaker. We found it in the Radio Electronics magazine of April 1990.
September 2016 - It can be obtained from Mouser Electronics new LED indicators for panel mounting...
This circuit can provide constant currents adjustable between 1 and 10 mA. The transistors can be...
This circuit is from American documentation from the 90s. The configuration is very current and can...