Variable Voltage Regulator
The op amp is wired as a 2 noninverting dc amplifier with a gain that is determined by the R3/R2 ratio. The inp
ut voltage to the op amp is variable between 0 and 15 V via R5. The output voltage is therefore variable over the approximate range from 0.5 to 30 V. The available output current has been boosted by adding transistor Ql to the output.