This 1988 circuit makes a back-and-forth of LEDs whose speed is controlled by P1. All components used are common and the circuit can be powered by voltages from 6 to 9 V.
This 1.2 to 32 V x 3 A regulator was found in an 80's EDN. The power components must be equipped...
Based on National Semiconductor's LM4130 reference circuit, this circuit was found in Internet...
Using a general-purpose transistor this AC amplifier was found in the November 1993 issue of...