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SMD code 2T-

Marking codes are not standardised, and the same code is reused by unrelated makers for unrelated parts. Below is every part in our tables printed with it, and any printed with a code that is easy to misread as it, from the manufacturers' own marking tables and published code lists.

81 parts are printed 2T-

Not sure which one you have?

Answer up to 4 quick questions and these 50 parts are ranked, with a meter test that settles it. It works on a dead part too.

  • LMBT4403WT1GSOT-323PNP transistor, 3 pins, LRCPNP transistorSOT-3233 pinsLRC
    What it is
    PNP transistor
    Maker
    LRC
    Package
    SOT-323
    Pins
    3
    Details
    Bipolar transistor, PNP, IC 600 mA, VCEO 40 V
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: PNP transistor.

  • MMBT2907ASOT-23PNP transistor, 3 pins, CYStekPNP transistorSOT-233 pinsCYStek
    What it is
    PNP transistor
    Maker
    CYStek
    Package
    SOT-23
    Pins
    3
    Details
    PNP bipolar transistor
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: PNP transistor.

  • MMBT4403SOT-23PNP transistor, 3 pins, Taitron ComponentsPNP transistorSOT-233 pinsTaitron Components
    What it is
    PNP transistor
    Maker
    Taitron Components
    Package
    SOT-23
    Pins
    3
    Details
    PNP bipolar transistor
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: PNP transistor.

  • MMBT4403-CSOT-23Transistor, 3 pins, SeCoSTransistorSOT-233 pinsSeCoS
    What it is
    Transistor
    Maker
    SeCoS
    Package
    SOT-23
    Pins
    3
    Details
    Bipolar transistor
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: Bipolar transistor.

  • MMBT4403-HFSOT-23PNP transistor, 3 pins, ComchipPNP transistorSOT-233 pinsComchip
    What it is
    PNP transistor
    Maker
    Comchip
    Package
    SOT-23
    Pins
    3
    Details
    -40 V, -0.6 A PNP transistor
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: PNP transistor.

  • MMBT4403-P2-HFSOT-23PNP transistor, 3 pins, ComchipPNP transistorSOT-233 pinsComchip
    What it is
    PNP transistor
    Maker
    Comchip
    Package
    SOT-23
    Pins
    3
    Details
    -40 V, -0.6 A PNP transistor
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: PNP transistor.

  • MMBT4403LSOT-23PNP transistor, 3 pins, onsemiPNP transistorSOT-233 pinsonsemi
    What it is
    PNP transistor
    Maker
    onsemi
    Package
    SOT-23
    Pins
    3
    Details
    Switching Transistor
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: PNP transistor.

  • MMBT4403QSOT-23PNP transistor, 3 pins, Yangjie Electronic TechPNP transistorSOT-233 pinsYangjie Electronic Tech
    What it is
    PNP transistor
    Maker
    Yangjie Electronic Tech
    Package
    SOT-23
    Pins
    3
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: PNP transistor.

  • MMBT4403TSOT-523PNP transistor, 3 pins, Galaxy MicroelectronicsPNP transistorSOT-5233 pinsGalaxy Microelectronics
    What it is
    PNP transistor
    Maker
    Galaxy Microelectronics
    Package
    SOT-523
    Pins
    3
    Details
    40V, 0.6A, General Purpose PNP Bipolar Transistor
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: PNP transistor.

  • MMBT4403WSOT-323PNP transistor, 3 pins, onsemiPNP transistorSOT-3233 pinsonsemi
    What it is
    PNP transistor
    Maker
    onsemi
    Package
    SOT-323
    Pins
    3
    Details
    PNP bipolar transistor
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: PNP transistor.

  • PMBT4403SOT-23PNP transistor, 3 pins, HXYPNP transistorSOT-233 pinsHXY
    What it is
    PNP transistor
    Maker
    HXY
    Package
    SOT-23
    Pins
    3
    Pinout
    • 1 base
    • 2 emitter
    • 3 collector
    Details
    Bipolar transistor, 40 V, 0.6 A
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: PNP transistor.

  • PMBT4403,215SOT-23PNP transistor, 3 pins, HXYPNP transistorSOT-233 pinsHXY
    What it is
    PNP transistor
    Maker
    HXY
    Package
    SOT-23
    Pins
    3
    Details
    Bipolar transistor, 40 V, 0.6 A
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: PNP transistor.

  • PMST4403SOT-323PNP transistor, 3 pins, NexperiaPNP transistorSOT-3233 pinsNexperia
    What it is
    PNP transistor
    Maker
    Nexperia
    Package
    SOT-323
    Pins
    3
    Details
    40 V, 600 mA PNP switching transistor
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: PNP transistor.

  • 2 more parts have no package on record

Is it dead? One meter test per kind

Parts of the same kind are tested the same way, so each test is here once. Each part above points to its own.

PNP transistor

Diode range, part lifted or its base leg off the pad.

Working, it reads

Black probe on the base reads about 0.6 to 0.75 V to the emitter and to the collector, and open the other way round. Collector to emitter reads open both ways.

Dead, it reads

  • Collector to emitter the same both ways, near 0 V with a continuous beep: shorted. The commonest failure.
  • The base the same both ways to another pin, near 0 V or a middling value: a shorted junction.
  • Only one junction reads, or none: a junction has failed open. It then looks like a diode.
  • A reading the wrong way round, where it should be open: leaky.
On the board
this is a first look only: the meter reads every path between those pins, and a short can be a neighbour. Lift one leg before you condemn it.
Compare:
If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.
Watch for:
A pair of diodes with a common pin reads just like a transistor, and some transistors carry a built-in diode or resistor. The datasheet says which.

A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

Bipolar transistor

Diode range, part lifted or its base leg off the pad.

Working, it reads

From the base, one probe colour reads about 0.6 to 0.75 V to the emitter and to the collector, and open the other way round. Collector to emitter reads open both ways.

Dead, it reads

  • Collector to emitter the same both ways, near 0 V with a continuous beep: shorted. The commonest failure.
  • The base the same both ways to another pin, near 0 V or a middling value: a shorted junction.
  • Only one junction reads, or none: a junction has failed open. It then looks like a diode.
  • A reading the wrong way round, where it should be open: leaky.
On the board
this is a first look only: the meter reads every path between those pins, and a short can be a neighbour. Lift one leg before you condemn it.
Compare:
If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.
Watch for:
A pair of diodes with a common pin reads just like a transistor, and some transistors carry a built-in diode or resistor. The datasheet says which.

A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

Voltage regulator

Voltage, board powered, black probe on ground. Then ohms with the power off.

Working, it reads

Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

Dead, it reads

  • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
  • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
  • Power off, input to output near 0 Ω: shorted.
On the board:
An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
Compare:
The same regulator on another rail or another board shows the right voltages and the right resistances.
Watch for:
Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

Zener diode

Diode range for the forward check, part lifted, red probe on the anode. A bench supply for the Zener voltage.

Working, it reads

About 0.6 to 0.8 V forward and open in reverse on the diode range. Its Zener voltage shows only on a supply: feed it through a resistor that sets about 5 mA, cathode to positive, read quickly, and it should hold near its rated voltage.

Dead, it reads

  • The same reading both ways round, near 0 V with a continuous beep or the same middling value: shorted.
  • Open both ways, forward too: failed open.
  • Holds well off its rated voltage on the supply test: drifted.
  • A soft knee, or a voltage that creeps on the supply test: leaky.
On the board
this is a first look only: the meter reads every path between those pins, and a short can be a neighbour. Lift one leg before you condemn it.
Compare:
If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.
Watch for:
A meter's diode range stops at about 2 to 3 V, so almost every Zener reads open in reverse on it, good or bad; a 3 V meter may just show a 2.4 or 2.7 V part. Above about 3 V the meter cannot tell a Zener from a plain diode.

A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

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