What Is the BC557? PNP Transistor: Pinout (C-B-E) and Uses
October 17, 2026 4 min read
Quick answer
The BC557 is a common, European-origin PNP bipolar transistor; the complement of the NPN BC547. It is used for small-signal and low-current (≤100 mA, −45 V) high-side switching. Its TO-92 pinout is C-B-E (the reverse of the American 2N3906). The A/B/C suffixes indicate gain grade.
The BC557 is a very common, European-origin PNP bipolar transistor (BJT) — the complement of the NPN BC547. It is used for small-signal and low-current high-side switching. For the concept, see what is a BJT.
BC557 pinout (TO-92) — C-B-E
Flat face front, left to right: C – B – E (the reverse of the American 2N3906!).
| Lead | Function |
|---|---|
| 1 | Collector (C) |
| 2 | Base (B) |
| 3 | Emitter (E) |
Specifications
| Parameter | Value |
|---|---|
| Type | PNP BJT |
| VCEO | −45 V |
| IC | −100 mA |
| hFE | ~110–800 (A/B/C grade) |
Equivalents
- BC547: the NPN complement.
- BC558/BC559: the same family.
- 2N3906: the American PNP equivalent (different pinout).
Find it in our catalog
Use the BC557 search.
Frequently Asked Questions
What is the BC557?+
The BC557 is a common, European-origin PNP bipolar transistor; it is the complement of the NPN BC547. It is used for small-signal and low-current (≤100 mA, −45 V) high-side switching.
What is the BC557 pinout?+
In TO-92, with the flat face front, left to right it is C-B-E. Note: the American 2N3906 is the reverse (E-B-C).
What is the difference between the BC557 and the BC547?+
The BC557 is PNP and the BC547 is NPN; the two are complements. Their pinouts are in the same order (C-B-E) but the biasing is opposite.
What is an equivalent for the BC557?+
The NPN complement BC547; the same family BC558/BC559; and the American PNP equivalent 2N3906 (different pinout).