The 2N3906 is the standard general-purpose PNP bipolar transistor, the direct complement of the NPN 2N3904, in a TO-92 through-hole package. It switches and amplifies small signals up to about 200 mA and 40 V with a current gain (hFE) of roughly 100 to 300, so it handles high-side switching, PNP current sources, and small-signal gain. Being PNP, it turns on when the base is pulled below the emitter. The TO-92 leads are E, B, C in order (pin 1 = emitter).

Pinout

Pin	Name	Type	Function
1	E	passive	Emitter of the PNP BJT. VEBO breakdown = 5.0 V (reverse). In normal PNP operation the emitter is the most positive terminal, with current flowing from emitter to collector.
2	B	input	Base of the PNP BJT. Control terminal; pulling the base below the emitter by ~0.65-0.85 V (VBE(sat)) forward-biases the B-E junction and turns the transistor on. IBL (base cutoff) = 50 nA max at VBE = 3.0 V.
3	C	passive	Collector of the PNP BJT. VCEO breakdown = 40 V (reverse), VCBO = 40 V, IC = 200 mA continuous. VCE(sat) = 0.25 V max at IC = 10 mA, IB = 1.0 mA. In normal PNP operation the collector sinks current toward the more-negative supply.

Key specifications

Parameter	Value
Type	PNP bipolar transistor
Collector-emitter (VCEO)	-40 V
Collector current (IC)	-200 mA
DC gain (hFE)	100-300
Transition freq (fT)	250 MHz
Power dissipation	625 mW
Pinout	E-B-C (pin 1 = emitter)
Package	TO-92

Ordering variants

2N3906BU (TO-92)
2N3906TA (TO-92, ammo pack)

CAD (KiCad official)

Symbol: Transistor_BJT:2N3906
Footprint: Package_TO_SOT_THT:TO-92_Inline
3D model: TO-92 (KiCad packages3D)

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

Datasheet: onsemi datasheet (6 pp, sha256 0173a9cdd84dfe57, retrieved 2026-08-17, tier: manufacturer)
Extractor: ds2sf (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF