LM317 Adjustable Positive Voltage Regulator
🔋 LM317 Adjustable Positive Voltage Regulator – TO-220
The LM317 is a versatile, adjustable positive linear voltage regulator capable of delivering 1.25V to 37V output with up to 1.5A current. Ideal for custom power supplies, battery chargers, and DIY electronics projects, the LM317 offers excellent load and line regulation, thermal protection, and current limiting.
⚙️ Technical Specifications
| Parameter | Specification |
|---|---|
| Input Voltage | 3V – 40V DC |
| Output Voltage | Adjustable (1.25V – 37V) |
| Output Current | Up to 1.5A (with heatsink) |
| Voltage Regulation | ±1% |
| Dropout Voltage | 2–3V (typical) |
| Package Type | TO-220 |
| Thermal Shutdown | Yes |
| Short Circuit Protection | Yes |
| Pin Configuration | 1. Adjust |
CopyEdit2. Output 3. Input
📌 Basic Application Circuit
To adjust output voltage:
VOUT=1.25V×(1+R2R1)+IADJ×R2V_{OUT} = 1.25V \times \left(1 + \frac{R2}{R1}\right) + I_{ADJ} \times R2VOUT=1.25V×(1+R1R2)+IADJ×R2
Typical resistor values:
R1 = 240Ω
R2 = 2KΩ for 12V output
🛠️ Applications
Adjustable power supply
Battery charger
Voltage regulation in DIY projects
LED drivers
Solar charge controllers
Lab bench power units
🧪 Arduino Use Example
Use it to power sensors or modules from a 12V input, stepped down to 5V or 3.3V using LM317 and resistors.
📦 Includes
1x LM317 Regulator (TO-220 package)