solderic.com The LM317 is a versatile adjustable voltage regulator offering output voltages from 1.25V to 37V, whereas the LM7805 is a fixed 5V voltage regulator known for its simplicity and reliability. To decide which voltage regulator suits Your project needs best, explore the detailed comparison in the rest of the article.
Comparison Table
| Feature | LM317 | LM7805 |
|---|---|---|
| Type | Adjustable Voltage Regulator | Fixed Voltage Regulator (5V) |
| Output Voltage | 1.25V to 37V (adjustable) | 5V (fixed) |
| Output Current | 1.5A Max | 1A to 1.5A Max |
| Input Voltage Range | 3V to 40V | 7V to 35V |
| Package | TO-220, TO-3, SOT-223 | TO-220, TO-3, SOT-223 |
| Adjustable Output | Yes (using external resistors) | No |
| Typical Applications | Custom voltage supplies, battery chargers | 5V regulated power supplies, microcontroller power |
| Thermal Overload Protection | Yes | Yes |
| Short Circuit Protection | Yes | Yes |
Introduction to LM317 and LM7805
LM317 is an adjustable voltage regulator capable of delivering output voltages from 1.25V to 37V with a current of up to 1.5A, offering flexibility in various electronic projects. LM7805 is a fixed 5V voltage regulator widely used for providing stable 5V power supply in circuits, ensuring reliable performance in digital electronics. Understanding your power requirements is crucial in choosing between LM317's adjustable output and LM7805's fixed voltage for optimal circuit functionality.
Key Specifications Comparison
The LM317 is an adjustable voltage regulator offering output voltages from 1.25V to 37V with a maximum current of 1.5A, while the LM7805 provides a fixed 5V output at up to 1A current. The LM317 requires two external resistors to set the output voltage, enabling flexibility, whereas the LM7805 is designed for simplicity with a single fixed voltage output. Your choice depends on whether you need a customizable voltage range or a reliable, preset 5V supply for your project.
Voltage Regulation Capabilities
The LM317 offers adjustable voltage regulation from 1.25V to 37V, providing flexible output for various applications, while the LM7805 delivers a fixed 5V output with simplicity and reliability. Your choice depends on whether you need a precise, stable 5V supply or a customizable voltage range for different circuit requirements. Both regulators maintain stable voltage under varying load and input voltage, ensuring consistent performance in power supply designs.
Output Current Ratings
The LM317 adjustable voltage regulator supports output currents up to 1.5 amperes, offering flexibility for a wide range of applications requiring variable voltage. In contrast, the LM7805 fixed voltage regulator typically provides a stable 5V output with a maximum current rating of 1 ampere. Designers choose the LM317 for higher current demands and adjustable voltage needs, while the LM7805 suits low-current, fixed 5V supply requirements.
Adjustable vs Fixed Output
The LM317 is an adjustable voltage regulator capable of outputting a wide range of voltages, typically from 1.25V to 37V, by using external resistors to set the desired voltage level. In contrast, the LM7805 is a fixed voltage regulator that provides a stable 5V output without requiring additional components for voltage adjustment. This makes the LM317 more versatile for custom voltage applications, while the LM7805 offers simplicity and reliability for standard 5V power supply needs.
Application Scenarios
The LM317 is ideal for adjustable voltage regulation in projects requiring a variable output, such as custom bench power supplies or battery chargers. The LM7805 offers a fixed 5V output, making it suitable for powering microcontrollers and digital circuits that demand a steady voltage. Your choice depends on whether you need flexibility in voltage levels or a reliable 5V supply for standard electronics.
Efficiency and Heat Dissipation
The LM317 offers adjustable output voltage, allowing for optimized efficiency in various applications, while the LM7805 provides a fixed 5V output with simpler design requirements but potentially higher power dissipation. Due to its adjustable nature, the LM317 can reduce heat generation by minimizing voltage drop, resulting in improved thermal management compared to the LM7805, which often requires larger heat sinks under similar load conditions. Efficiency differences are particularly notable in low-voltage, high-current scenarios where the LM317's flexibility helps maintain cooler operation and longer component lifespan.
Circuit Complexity and Design
The LM317 voltage regulator offers adjustable output, requiring a more complex circuit design with external resistors to set the desired voltage, whereas the LM7805 provides a fixed 5V output with a simpler, more straightforward circuit. Your choice depends on whether you need flexibility in voltage regulation or prefer ease of implementation and fewer components. Designing with the LM317 allows for fine-tuning, while the LM7805 is ideal for standardized 5V power supplies with minimal circuit complexity.
Cost and Availability
The LM317 typically offers greater flexibility with adjustable output voltage, often available at a similar or slightly lower cost compared to the fixed 5V output LM7805. Both regulators enjoy widespread availability from major electronic component distributors, though the LM7805 is a more common choice in legacy applications, potentially affecting pricing and stock levels. You can easily source either component for low-cost power regulation solutions depending on your specific voltage requirements.
Choosing the Right Regulator
Choosing the right voltage regulator depends on your project's voltage and current requirements. The LM317 offers adjustable output voltage ranging from 1.25V to 37V with a maximum current of 1.5A, making it versatile for custom voltage settings. Your selection between the LM317 and fixed 5V output LM7805 should consider whether you need a precise 5V supply or variable voltage flexibility.
LM317 vs LM7805 Infographic
