LM317 Constant Current Source Power Supply Circuit

LM317 Constant Current Source Power Supply

LM317 Constant Current Power Supply Circuit Diagram

LM317 constant current source power supply circuit  electrobuff.blogspot.com

LM317 Constant Current Power Supply Circuit Overview

What's up electronics fans? In today's tutorial I'll show you how to make a simple constant current source power supply based on the LM317 linear regulator IC.

The output current fed to the load remains constant as determined by the limiting resistor regardless of a variation of the input supply voltage as long as it's within the regulator IC input voltage thresholds.

LM317 constant current source power supply circuit  electrobuff.blogspot.com

LM317 constant current source power supply circuit  electrobuff.blogspot.com

LM317 constant current source power supply circuit  electrobuff.blogspot.com

Watch my YouTube Video Tutorial

https://youtu.be/yzcomGhHhZU?si=Plt0ZrXs4-a3H-71

LM317 Linear Regulator IC Overview

The LM317 is a versatile voltage regulator integrated circuit (IC) that has been widely used in electronic circuits since its introduction by National Semiconductor (now part of Texas Instruments) in the 1970s. It is a three-terminal adjustable positive voltage regulator, meaning it can be configured to provide a regulated output voltage within a specified range.

LM317 linear voltage regulator IC Pinout  electrobuff.blogspot.com

LM317 linear voltage regulator IC Pinout  electrobuff.blogspot.com

Key Features of LM317:

Adjustable Output Voltage: One of the primary features of the LM317 is its ability to provide a variable and adjustable output voltage. By using external resistors, the user can set the desired output voltage within a specified range.

Wide Input Voltage Range: The LM317 can operate with a wide input voltage range, making it suitable for various applications. It can handle input voltages significantly higher than the desired output voltage.

Low Dropout Voltage: The dropout voltage is the minimum voltage required between the input and output for the regulator to maintain regulation. The LM317 has a low dropout voltage, enabling it to regulate the output even when the input voltage is close to the desired output voltage.

High Ripple Rejection: The IC exhibits high ripple rejection, which means it can effectively filter out AC voltage variations in the input, providing a stable DC output.

Current Limiting: The LM317 has built-in current limiting to protect the device from excessive currents. This feature enhances the reliability of the IC in various applications.

Thermal Shutdown: To prevent overheating, the LM317 includes a thermal shutdown mechanism. If the temperature exceeds a certain threshold, the IC will shut down temporarily until it cools down.

TO-220 Package: The LM317 is commonly available in a TO-220 package, making it easy to handle and dissipate heat. This package is widely used in electronic circuits and allows for easy mounting on heat sinks.

Common Applications:

Voltage Regulator: The primary application of the LM317 is as a voltage regulator to provide a stable and adjustable output voltage for powering electronic devices.

Power Supplies: The LM317 is frequently employed in the design of linear power supplies for various electronic systems, including hobbyist projects and commercial applications.

Battery Chargers: It is used in battery charging circuits to regulate the charging voltage for lead-acid batteries, Ni-Cd batteries, and other types.

Audio Amplifiers: The LM317 can be utilized in audio amplifier circuits to provide a stable supply voltage for amplifier components.

Instrumentation and Control Systems: Due to its versatility, the LM317 finds applications in instrumentation and control systems where a stable and adjustable voltage is required.

The LM317's enduring popularity stems from its reliability, ease of use, and adaptability to a wide range of voltage regulation tasks in diverse electronic applications.