BC557 PNP Transistors and BC547/BC557 Kits
Compare BC557 PNP bipolar transistors, BC547/BC557 complementary selections and mixed TO-92 transistor assortments. Several product pages share a title across many selectable models: choose BC557 or BC557B/BC557C explicitly if you need that device. Other choices in this collection include NPN transistors, other PNP models, a voltage reference, MOSFETs and regulators within larger shared menus.
BC557 models and package choices
- Through-hole BC557: multi-model TO-92 listings let you select BC557, BC557B or BC557C rather than other BC-series devices. A shared page lists a BC557B 100-piece option, while another offers 50 pieces of the selected model. Check the chosen model and count; the word “Color” often identifies the part number, not its appearance.
- Surface mount: a separate BC557C listing describes SOT-23 and offers 50-piece or 100-piece quantities. The surface-mount footprint is not the same as TO-92. Product headlines and seller-origin claims are not substitutes for the actual manufacturer's datasheet or traceability documentation.
- Complementary packs: BC547/BC557 listings include an option labeled 50 pairs, separate 100-piece BC557B and BC547B packs, a 50-piece kit described as 25 of each, and other selections labeled 25 pieces of one type or a mixed pack. Read each variant carefully: “50 pairs” and “50 pieces total” represent different counts, and paired models are not guaranteed gain-matched.
- Mixed assortments: 10-value 100/200-piece TO-92 kits, 24-value 480-piece kits and a 24-value 840-piece box are listed. One box also has 1BOX and 3BOX choices. Check each packing list; BC557 is only one model in a multi-value set. A listing described as “10 values, each 10 pieces” also claims 250 pieces elsewhere in its text, so its total should be confirmed on that product page rather than inferred from the headline.
Do not confuse neighboring selections
BC547, BC548, BC549, BC550, BC337 and BC639 are NPN choices; BC556, BC558, BC560, BC327 and BC640 are different PNP models. BC517 is a Darlington-type transistor with different input behavior. A shared assortment menu also offers TL431A voltage reference, 2N7000 MOSFET and 78L/79L regulators. None of these are BC557 substitutes merely because they appear on a BC557 product page. The B and C suffixes distinguish gain group selections; compare the complete model and manufacturer-specific electrical limits.
BC557 selection checklist
- Choose the exact BC557 variant and specified gain suffix if your design requires one. Confirm PNP polarity, package, pin assignment and PCB footprint. Do not assume SOT-23 and TO-92 versions can be dropped into the same board.
- Compare the selected manufacturer's datasheet for collector-emitter voltage, collector current, gain at the intended operating point, saturation voltage, power dissipation and operating temperature under your actual conditions. Shared seller text such as “international standard” is not a numeric rating.
- Check whether the purchase is a single-model pack, one of two selectable models, a complementary pair or a mixed assortment. Inspect quantities per model and any conflicting count claims before ordering.
Frequently asked questions
Is BC557 the same transistor as BC547?
No. BC557 is PNP and BC547 is NPN. Their complementary use in a design does not make them interchangeable, and you should verify both exact datasheets and pinouts.
Does a BC557B or BC557C suffix matter?
Yes. The suffix identifies a gain classification; use the full part number and the relevant manufacturer's specifications when choosing a replacement.
Does the 200-piece kit contain 200 BC557 devices?
No when it is a 10-value assortment. A listing describing 20 pieces of each of 10 types includes BC557 as one type; inspect the selected kit's contents and count.
Can I use a SOT-23 BC557C in a TO-92 board?
Not as a direct physical replacement. Package and pin mapping must be checked, and any adaptation must be designed for the chosen part.
