Earth Bondhon
Creators
Earth Bondhon Author
Earth Bondhon
CalculatorToolsProjectExpert
Reviewers
Małgorzata Koperska, MD Steven Wooding
Last updated: August 4, 2025

Adjustable Voltage Regulator Circuit DIY Project

🇺🇸
English
Default
🇪🇸
Español
Spanish
🇫🇷
Français
French
🇩🇪
Deutsch
German

Components List

TIP41C Transistor

TIP41C Transistor

NPN power transistor with high current (6A) & voltage (100V) ratings

50K Fixed Resistor

50K Variable Resistor

Adjustable resistor with 50,000 ohm resistance

6.8R Fixed Resistor 5W

6.8R Fixed Resistor 5W

A 6.8-ohm resistor rated for 5 watts

*Please note: These are affiliate links. I may make a commission if you buy the components through these links. I would appreciate your support in this way!

Adjustable Voltage Regulator Project

Learn how to make an adjustable voltage regulator using LM317 or LM338. Perfect for DIY electronics projects requiring a variable DC output voltage.

12v battery indicator using LED

The 12V charging indication circuit offers an easily understandable and accurate method of knowing the charging status of a 12V battery using simple components. With the inclusion of a comparator voltage or switching logic transistor, this circuit can allow users to effectively monitor battery health and curb battery overcharging. It is a vital instrument in the automotive, solar, and do-it-yourself electronics-related projects involving lead-acid or lithium batteries.

variable voltage diy kit Formula:

  • Output Voltage: Vout = 1.25 × (1 + R2/R1) + Iadj × R2
  • R1: Typically 240Ω
  • R2: Adjustable resistor or potentiometer
  • Input Voltage: Minimum 3V higher than desired output
  • Capacitors: Cin = 0.1µF, Cout = 1µF or more

adjustable voltage regulator project

A voltage adjustable circuit is made to adjust the output voltages over a range best suited for testing, prototyping, and a variable power supply. The components that are incorporated in this project generally include variable resistors (potentiometers), LM317 or LM338 regulators, capacitors, and heat sinks so that adjustable results can be handled in a reliable and efficient manner. The users can adjust resistance in the circuit by rotating the potentiometer and affecting the output voltage. It has many applications in self-construct projects, charging batteries, and power management customized set-ups.

diy variable power supply

R1 (Ω)R2 (Ω)Output Voltage (V)
2404703.7
24010006.5
240180010.6

Frequently Asked Questions - Adjustable Voltage Regulator Project:

What is an adjustable voltage regulator?

It is a circuit that allows output voltage control using components like LM317.

Which IC is best for variable voltage?

LM317 is widely used for 1.25V to 37V output range.

Can I use a potentiometer to adjust voltage?

Yes, a potentiometer is used as R2 in the voltage divider.

What is the input voltage range for LM317?

Typically 3V to 40V depending on the application.

Do I need a heatsink?

Yes, if output current exceeds 500mA, a heatsink is recommended.

What is Iadj in the formula?

A small adjustment pin current, often neglected in calculations.

How accurate is LM317?

It provides ±1.5% voltage accuracy under typical conditions.

Can I use LM317 for battery charging?

Yes, but with current limiting and careful design.

Is filtering needed?

Input and output capacitors improve stability and filtering.

Can I use LM338 for higher current?

Yes, LM338 handles up to 5A with proper heatsinking.

Earth Bondhon

Earth Bondhon

CalculatorToolsProject

Md. Jony Islam is a highly skilled professional with expertise in electronics, electrical, mechanical, and civil engineering, as well as finance. Specializing intransformer service and maintenance for 33/11kV substations, he ensures reliable and efficient electrical systems. His mechanical engineering skills drive innovative designs, while his financial acumen supports effective project budgeting. With a strong foundation in civil engineering, he contributes to robust infrastructure development. Md. Jony Islam's multidisciplinary approach ensures efficiency, quality, and reliability across all projects.