LM317T Adjustable Voltage Regulator

The LM317T is a versatile adjustable linear voltage regulator capable of delivering a stable output voltage from 1.2 V to 37 V. Housed in a TO‑220 package, it can supply up to 1.5 A with proper heatsinking, making it ideal for power supplies, prototyping, and general electronics projects.

Overview

The LM317T is one of the most widely used adjustable voltage regulators in electronics. Using just two external resistors, the output voltage can be set anywhere from 1.2 V up to 37 V, providing excellent flexibility for both fixed and variable power supply designs. Its internal current limiting, thermal shutdown, and safe‑area protection make it robust and reliable, even in demanding applications.

Key Features

• Adjustable output voltage: 1.2 V to 37 V
• Output current up to 1.5 A (with adequate heatsinking)
• TO‑220 package for easy mounting and cooling
• Built‑in thermal overload protection
• Short‑circuit and safe‑area protection
• Requires only two external resistors to set output voltage

Typical Applications

• Bench and lab power supplies
• Arduino and microcontroller projects
• Battery chargers
• Post‑regulation for switching power supplies
• Educational and prototyping circuits

Notes for Designers

• Input voltage must exceed output voltage by approximately 2–3 V
• Adequate heatsinking is required at higher currents or voltage drops
• Output capacitor recommended for improved stability

See datasheet for more information.