5 V voltage regulator · TO-220
7805 Pinout
Printed face toward you, metal tab at the back, legs pointing down, left to right: 1 input, 2 ground, 3 output (IN-GND-OUT). The metal tab is joined to the ground.
The classic fixed 5 V regulator: 7.5 V to 35 V in, a steady 5 V out, and 1 A to 1.5 A depending on the maker.
- Pin 1: Input (IN)The unsteady supply comes in here: at least about 7.5 V for a 5 V output, never above 35 V.
- Pin 2: Ground (GND)0 V, shared by the input and the output. Also joined to the metal tab, on the TO-220 that has one.
- Pin 3: Output (OUT)A steady 5 V comes out here.
Metal tab: joined to pin 2, the ground, inside the part.
Check your part before wiring. Read the maker and the full part number printed on it, open that maker's datasheet, or test the legs with a multimeter's diode setting.
PNG 1440 × 1280 pixels, SVG to any size. Both keep the wirecora.com mark along the bottom.
Pinout table
Which leg of the 7805 is which?
| Pin | Name | What it does |
|---|---|---|
| 1 | Input IN | The unsteady supply comes in here: at least about 7.5 V for a 5 V output, never above 35 V. |
| 2 | Ground GND | 0 V, shared by the input and the output. Also joined to the metal tab, on the TO-220 that has one. |
| 3 | Output OUT | A steady 5 V comes out here. |
| Tab | Metal tab GND | Joined to pin 2, the ground, so it carries the same voltage. Keep it away from other metal unless you mean it to touch. |
Key ratings
How much can the 7805 take?
From the Texas Instruments datasheet: LM340, LM340A and LM7805 Family Wide VIN 1.5-A Fixed Voltage Regulators (SNOSBT0L). Stay well inside these limits: they are the most the part takes, not what it should run at.
Open the Texas Instruments datasheet (PDF)Pin order by maker
Is every 7805 wired IN-GND-OUT?
The TI datasheet numbers the legs 1 input, 2 ground, 3 output (IN-GND-OUT) with the printed face toward you; in the metal-tab TO-220 the tab is ground. Other makers' 7805s normally use the same order.
The tab is ground only where there is a metal tab: the fully plastic TO-220FP version (for example ST's L7805CP) has no exposed tab. How much current a 7805 gives also depends on the maker: TI's LM340 and ST's L78 are rated 1.5 A, onsemi's MC7805 "in excess of 1.0 A".
The negative regulators (7905 and the rest of the 79xx family) use a different order with the tab on the input. Do not swap one into a 7805's place.
A first circuit
5 V for an Arduino or sensors from a 9 V or 12 V supply
- Supply plus to IN, supply minus to GND.
- A 0.22 µF capacitor from IN to GND, close to the regulator (TI's datasheet asks for it when the supply's own capacitor is far away).
- A 0.1 µF capacitor from OUT to GND helps when the load changes quickly.
- Take 5 V from OUT and 0 V from GND.
The regulator turns the extra voltage into heat: from 12 V at 0.5 A that is 3.5 W, which needs a heatsink. From a 9 V battery it works, but the battery does not last long.
7805 questions
What is the 7805 pinout?
With the printed face toward you and the legs down, from left to right: input, ground, output (IN-GND-OUT). On the usual metal-tab TO-220 the tab is ground; the fully plastic TO-220FP has no exposed tab.
What is the lowest input voltage for a 7805?
About 7 to 7.5 V. The regulator needs about 2 V more on its input than the 5 V it gives out. Below that, the output sags with the input.
Why does my 7805 get hot?
Every volt it drops, times the current, is heat. 12 V in and 5 V out at 0.5 A is 3.5 W. Give it a heatsink, lower the input voltage, or use a switching regulator module.
Do I need capacitors on a 7805?
TI's datasheet uses 0.22 µF on the input when the supply's filter capacitor is far away, and says 0.1 µF on the output is not needed for stability but helps with fast load changes. Fit both: they cost almost nothing.
Can I use this pinout picture?
Yes. Download it as PNG or SVG and use it in notes, lessons or posts. The wirecora.com mark along the bottom stays in the picture.
Pin order and ratings from the Texas Instruments datasheet named above. Last reviewed .