2N3904 Pinout
2N3904 NPN Transistor · Extremely common NPN small-signal transistor.
TO-92: with the flat face toward you and the pins down, left to right is E-B-C.
| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | E · Emitter | I/O | Emitter |
| 2 | B · Base | Input | Base (control) |
| 3 | C · Collector | Output | Collector |
How to read the 2N3904 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
Do the 2N3904 and 2N2222 have the same pinout?
TO-92 plastic packages both follow E-B-C (flat face toward you). But their current capabilities differ: the 3904 is about 200mA, the 2222A about 800mA.
What is the matching PNP?
The 2N3906 is the PNP complement of the 2N3904, often paired for push-pull.
Pinout data comes from onsemi 2N3904 datasheet (standard TO-92 numbering). Refer to the actual device datasheet as authoritative for the pinout.