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2N3906 transistors in plastic TO-92 packaging. The cases are marked with E, B, and C for lead identification.
Photomicrograph of the transistor chip inside a 2N3906 transistor package, showing the conductive metal layers used to connect the semiconductor junctions to the package leads. The upper-left and lower-right quadrants are bonding pad areas where wires for two of the terminals are attached, and the other two quadrants have the actual transistor structures, in a bulk region that is contacted at the back side of the chip to the third terminal.


The 2N3906 is a commonly used PNP bipolar junction transistor intended for general purpose low-power amplifying or switching applications. It is designed for low electric current and power and medium voltage, and can operate at moderately high speeds.

The 2N3906 is manufactured in a plastic TO-92 case. When looking at the flat side with the leads pointed downward, the three leads emerging from the transistor are, from left to right, the emitter, base, and collector leads.

The 2N3906 is specified by a collector current of 200 mA, collector-base and collector-emitter voltages of 40 V, for power dissipation of 300 mW. Its transition frequency Ft is 250 MHz, with a beta of at least 100.[1]

The complementary NPN transistor to the 2N3906 is the 2N3904.[2] Both types were registered by Motorola Semiconductor in the mid-1960s.

Part numbers[edit]

The 2N3904 (NPN) and 2N3906 (PNP) are complementary transistor pairs.

Transistor part numbers[2][1]
BJT Thru-hole Surface-mount
TO92 SOT23 SOT223
NPN 2N3904 MMBT3904 PZT3904
PNP 2N3906 MMBT3906 PZT3906

See also[edit]


Further reading[edit]

Historical Databooks

External links[edit]