The variable voltage regulator lets you adjust the output voltage of a fixed de power supply between 1.2 and 37 V de, and will supply the output current in excess of 1.5 A. The circuit incorporates an LM117K three-terminal adjustable output positive voltage regulator in a T0-3 can. Thermal overload protection and short-circuit current-limiting constant with temperature are included in the package.
Capacitor C1 reduces sensitivity to input line impedance, and C2 reduces excessive ringing. Diode CR1 prevents C2 from discharging through the IC during an output short.