78L05 Pinout
78L05 100mA Voltage Regulator · Fixed +5V linear regulator, 100 mA, in a TO-92 — the small-current sibling of the 7805.
🛑 Gotcha: in the TO-92 package, flat (printed) face toward you and pins down, left to right is OUT-GND-IN — this is the REVERSE of the TO-220 7805 (which is IN-GND-OUT). Wiring a 78L05 like a 7805 swaps input and output.
| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | OUT | Output | Regulated +5V output |
| 2 | GND | GND | Ground / common |
| 3 | IN · VIN | Power | Unregulated input (≈7–30V) |
How to read the 78L05 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
Is the 78L05 pinout the same as the 7805?
No — and this is a common mistake. The TO-92 78L05 is OUT-GND-IN (flat face toward you, pins down), whereas the TO-220 7805 is IN-GND-OUT. The two are mirror images, so do not copy a 7805 layout for a 78L05.
How much current can the 78L05 supply?
About 100 mA — it is the low-current version of the 7805 (which handles ~1A). Use it for small logic loads; for more current step up to a 7805 in TO-220 with a heatsink.
Pinout data comes from STMicroelectronics L78L00 series datasheet (standard TO-92 numbering). Refer to the actual device datasheet as authoritative for the pinout.