Hello friends! Today we will build an adjustable DC supply using an LM317 voltage regulator in Proteus. We will calculate the output-setting resistors, check the available voltage range, and see why load current and temperature matter as much as the potentiometer setting. Our earlier 5 V supply using a 7805 provides a fixed output. The LM317 uses an external resistor network to set its output, making it useful when a project needs a different low-voltage supply. It does not, however, provide every voltage from zero to the input voltage. The original motor demonstration, images, video and download remain in this tutorial. We will explain the historical readings while correcting its missing LED current limiter, capacitor choices and assumptions about the maximum output. Start with a resistiv ...