Found in a 90s Radio Electronics, this circuit can supply currents of a few amps, according to the power transistor. The power transistor must be equipped with a heat sink.
This filter, which rejects frequencies around 1 kHz, was found in the August 1993 Electronics Now...
This is a voltage regulator circuit for currents up to 1.5 A with an output voltage adjustment for outputs...
This circuit uses an operational amplifier that is still common today. The indication is made by...