# Variable Voltage Regulator – Ninna Wiends

By | March 20, 2022

Variable voltage regulator
is a regulator circuit that has an output voltage that can be varied as needed. Variable voltage regulator circuits are currently available in the form of a 3-pin variable voltage regulator IC chip. One example of a variable voltage regulator is the LM317 IC.
IC LM317 is a variable voltage regulator IC chip for positive DC voltage. To make a power supply with a variable output voltage can be made simply by using the LM317 regulator IC. LM317 . variable voltage regulator IC consists of the following internal circuit.

### LM317 Internal Internal Circuit ### Functions of the part of the LM317 . positive voltage regulator

• Voltage Reference is a line or part that functions to provide a reference voltage for the control of the output voltage on the LM317 regulator. The reference voltage input is taken from the variable voltage divider circuit (R1 and R2 in the circuit below).
• Comparator serves as a comparison between the output voltage and the reference voltage, where the magnitude of the output voltage can be calculated from the equation below.
• Circuit Protection is a protective circuit IC LM317 from the occurrence of short circuits and as a protective IC from overheating.
• power regulator is an NPN transistor darlinto design that serves to amplify the output current of the LM317 variable voltage regulator.

The LM317 variable voltage regulator IC has the ability to carry a maximum current of 1.5 Ampere and is able to provide variable output voltage from 1.2 volts DC to 37 volts DC. An example of the application of the LM317 variable voltage regulator can be seen in the following figure.

### LM317 . Variable Voltage Regulator Circuit

Voltage regulator circuit
The above variable uses IC LM317 so that the regulator circuit becomes simple. The supporting components of the LM317 variable voltage regulator are basically a combination variable voltage divider circuit R1 and R2. Capacitors Ci and Co function as input and output filters. the reference voltage value on the voltage regulator above is determined based on the position of the lever R2. The magnitude of the output voltage at variable voltage regulator with IC LM317 (Vo) above can be calculated by the following equation.

### LM317 . Variable Voltage Regulator Specifications

• Maximum current 1.5 Ampere
• Can provide output changes from 1.2 volts to 37 volts DC
• Equipped with protection from short circuit (shot circuit.
• Equipped with over heating protection (overheating)

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