L7812 Positive Voltage Regulator
Fixed 12V Linear Regulator for Stable Power Supply Circuits
The L7812 is a three-terminal positive voltage regulator from the 78xx series. It provides a fixed, stable +12V output from a higher, unregulated DC input voltage [citation:1][citation:2]. This makes it a key component for powering circuits that require a clean and reliable 12V supply.
Fixed 12V Output - Provides a stable 12V DC output for consistent circuit operation.
Indestructible Design Builtin protection against overheating and short circuits ensures durability [citation:1].
Typical Input Voltage Range: 14V to 27V DC (Minimum around 14.5V-19V) [citation:1][citation:7][citation:9].
Maximum Output Current: 1.5A (with adequate heatsinking) [citation:1][citation:5].
The L7812 is a linear regulator, meaning the difference between input and output voltage is dissipated as heat. A heatsink is highly recommended for currents over 1A [citation:2].
Technical Specifications
| Parameter | Value |
|---|
| Output Voltage | 12V Fixed (±2% for 'A' version) [citation:1][citation:5] |
| Input Voltage (Typical) | 14.5V to 27V DC [citation:7] |
| Input Voltage (Max) | 35V DC [citation:1][citation:4] |
| Output Current | Up to 1.5A [citation:1] |
| Package | TO-220, D2PAK, etc. [citation:4][citation:8] |
| Protection | Thermal Shutdown, Short Circuit Protection [citation:1][citation:3] |
= Pin Configuration (TO-220 Package) =
When viewed from the front with the metal tab facing up and pins pointing down:
- *Pin 1:* Input (Unregulated DC voltage) [citation:9]
- *Pin 2:* Ground (Common) [citation:2]
- *Pin 3:* Output (Stabilized +12V) [citation:9]
Use a small heatsink to prevent the IC from overheating during operation [citation:2].
For applications requiring high current, consider using a switching regulator to reduce heat generation.
Ensure the input voltage does not exceed 35V to prevent permanent damage [citation:1][citation:4].
Troubleshooting
No or incorrect output voltage:
- Verify input voltage is at least 14.5V and not exceeding 35V.
- Check the load current does not exceed 1.5A.
- Inspect for adequate heatsinking to prevent thermal shutdown.
