2N3904 Transistors and Mixed BJT Kits
Shop 2N3904-family NPN small-signal bipolar transistors alongside related MMBT3904 surface-mount selections and transistor assortment kits. The collection includes TO-92 model-choice packs, SOT-23 MMBT3904 packs, and boxes in which 2N3904 is one of several models. It is not an all-2N3904 collection: shared menus and mixed kits also contain PNP transistors and, in some cases, MOSFETs, diodes or a voltage reference. Choose the actual variant before applying any headline specification.
Formats and pack contents
- TO-92 model-choice packs: listings with 2N3904 in the headline may let you select 2N3906, 2N2222, 2N2907, 2N4401/4403, 2N5401/5551 or 2N5087/5088/5089 instead. The selected model is typically one model per bulk pack, not the entire headline list. 2N3906 is PNP; 2N3904 is NPN.
- SOT-23 model-choice packs: MMBT3904 (including 1AM-marked listings) and MMBT3906 (2A-marked listings) appear in shared menus, with quantities such as 10 or 100 pieces and a separate bulk headline. Other SOT-23 menus add MMBT2222A, MMBT2907A and MMBT5551. A displayed “Voltage” option or a 40 V/200 mA headline is not a datasheet for every selected transistor.
- Actual transistor assortments: TO-92 boxes include 2N3904 with other NPN types and PNP types such as 2N3906, A1015, BC327 or S8550. Examples include 180 pieces across 18 kinds (10 each), 200 pieces across 10 types (20 each), and 600 pieces across 15 types (40 each); other menus offer 100-, 160-, 170-, 300-, 480- or 900-piece versions. Verify the contents for the chosen kit; a BC327/BC558-focused configuration may not contain 2N3904 even when its product headline does.
- Mixed electronic-component sets: 350-piece SMD transistor-and-diode assortments list 2N3904 together with 2N3906, 2N7002 MOSFET, 1N4148 and BAT54/BAV diodes. One SOT-23 210-piece kit names TL431 as well. 2N7000/2N7002 and TL431 are not NPN BJTs; do not select them as 2N3904 equivalents.
Selection checklist
- Confirm the selected full part number, NPN versus PNP polarity, and whether the order is a single-model pack or a multi-model assortment. Options labeled “Color” or “Voltage” can represent a model or kit quantity rather than their literal labels.
- Check the selected manufacturer's datasheet for collector-emitter voltage, collector current, gain at the intended operating current, saturation behavior, switching conditions, power dissipation and temperature derating. Do not treat generic seller figures as verified ratings for all options.
- Compare package and pinout: TO-92 2N3904 and SOT-23 MMBT3904 require different footprints, and lead mapping must be checked against the exact manufacturer drawing.
- For a replacement or design change, check electrical and thermal margins rather than substituting a 2N2222, 2N3906 or MOSFET solely because it appears in the same assortment.
Frequently asked questions
Is 2N3906 the same as 2N3904?
No. 2N3906 is a PNP-family transistor, whereas 2N3904 is NPN. A shared listing does not make their polarities interchangeable.
Does a “10-value” headline ship all ten transistor models?
Not necessarily. Some products offer separate model options while others are actual mixed boxes. Read the chosen variant and its included-model quantities.
Can MMBT3904 replace a through-hole 2N3904?
Not mechanically as-is. Compare the exact datasheets, lead arrangement, SOT-23 versus TO-92 footprint and thermal conditions first.
Are the 350-piece SMD kits all transistors?
No. Their component lists also include diodes and a MOSFET option. Check the contents before using them as a BJT assortment.
