L7812 Pinout
L7812 12V Voltage Regulator · Classic fixed 12V linear regulator (78xx family), input ≤35V.
TO-220 front (printed face) toward you, pins down: left to right IN-GND-OUT (same as the 7805). The tab is tied to GND. Needs input ≥ ~14.5V for regulation.
| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | IN · Vin | Power | Input voltage (14.5–35V) |
| 2 | GND | GND | Ground (tied to the tab) |
| 3 | OUT · Vout | Output | Regulated +12V output |
How to read the L7812 pinout
- 01
Find pin 1
One end of the chip has a half-circle notch or a dot; with the notch facing up, the top-left pin is pin 1.
- 02
Count counter-clockwise
Count counter-clockwise from pin 1: go down the left side first, then up the right side from the bottom.
- 03
Check the table below
Look up each pin's function by number in the table below; power/ground are color-coded, and alternate-function signals are in parentheses.
Frequently asked questions
What is the pin order of the L7812?
Printed face toward you, pins down: left to right IN-GND-OUT — the same layout as the whole 78xx family. The metal tab is internally connected to GND.
What is the minimum input voltage?
About 14.5V. A 78xx regulator needs roughly 2–2.5V of headroom above its output, so 12V out needs ≥ ~14.5V in to stay regulated.
Do I need capacitors and a heatsink?
Add ~0.33µF at the input and ~0.1µF at the output for stability. All of (Vin−12V)×Iout is dissipated as heat, so a heatsink is needed at higher currents or input voltages.
Pinout data comes from ST/TI L7812 datasheet (standard TO-220 numbering). Refer to the actual device datasheet as authoritative for the pinout.