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SMD code T1

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.

10 parts are printed T1

Not sure which one you have?

Answer up to 4 quick questions and these 10 parts are ranked, with a meter test that settles it. It works on a dead part too.

  • BCX17SOT-23PNP transistor, 3 pins, Nexperia
    What it is
    PNP transistor
    Maker
    Nexperia
    Package
    SOT-23
    Pins
    3
    Source
    From the manufacturer's datasheet

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

  • BZX84-B9V1SOT-23Zener diode, 3 pins, Nexperia
    What it is
    Zener diode
    Maker
    Nexperia
    Package
    SOT-23
    Pins
    3
    Pinout
    • 1 anode
    • 2 not connected
    • 3 cathode
    Details
    9.1 V ±2% voltage regulator (Zener) diode
    Source
    From the manufacturer's datasheet

    Is it dead? The meter test is below: Zener diode.

  • BZX384-C6V2SOD-323Zener diode, 2 pins, Nexperia
    What it is
    Zener diode
    Maker
    Nexperia
    Package
    SOD-323
    Pins
    2
    Source
    From the manufacturer's datasheet

    Is it dead? The meter test is below: Zener diode.

  • EMT1SOT-563PNP transistor, 6 pins, JSCJ
    What it is
    PNP transistor
    Maker
    JSCJ
    Package
    SOT-563
    Pins
    6
    Details
    Bipolar transistor, PNP
    Source
    From the manufacturer's datasheet

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

  • MMBD914SOT-23Switching diode, 3 pins, Panjit
    What it is
    Switching diode
    Maker
    Panjit
    Package
    SOT-23
    Pins
    3
    Details
    Surface-mount fast switching diode
    Source
    From the manufacturer's datasheet

    Is it dead? The meter test is below: Silicon diode.

  • MMBD914TSSOD-523Switching diode, 2 pins, Panjit
    What it is
    Switching diode
    Maker
    Panjit
    Package
    SOD-523
    Pins
    2
    Source
    From the manufacturer's datasheet

    Is it dead? The meter test is below: Silicon diode.

  • MMBT4413SDWSOT-363Transistor, 6 pins, Diotec
    What it is
    Transistor
    Maker
    Diotec
    Package
    SOT-363
    Pins
    6
    Details
    SMD General Purpose NPN | PNP Transistors
    Source
    From the manufacturer's datasheet

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

  • MMBT5451SDWSOT-363Transistor, 6 pins, Diotec
    What it is
    Transistor
    Maker
    Diotec
    Package
    SOT-363
    Pins
    6
    Details
    SMD General Purpose NPN | PNP Transistors
    Source
    From the manufacturer's datasheet

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

  • UMT1NSOT-363PNP transistor, 6 pins, JSCJ
    What it is
    PNP transistor
    Maker
    JSCJ
    Package
    SOT-363
    Pins
    6
    Details
    Bipolar transistor, PNP
    Source
    From the manufacturer's datasheet

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

  • 1 more part has 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.

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.

TVS or ESD protection diode

Diode range, from the protected line to ground, part lifted if you can.

Working, it reads

A one-way part reads about 0.6 to 0.8 V forward and open in reverse. A two-way part reads open both ways. Arrays with several lines read as the datasheet's diagram draws them.

Dead, it reads

  • From the line to ground, the same reading both ways, near 0 V with a continuous beep: shorted.
  • A reading both ways on a one-way part: leaky.
  • A one-way part open both ways: failed open.
On the board
, a line reading shorted to ground can be this part or anything else on that line. Lift it: if the short goes with it, it has failed.
Compare:
The same part on the next line or connector pin is the healthy reading to compare with.
Watch for:
A two-way part reads open both ways when it is good, exactly like one that has failed open. The meter cannot tell them apart; an identical part on the next line can.

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

Silicon diode

Diode range, part lifted or one leg off the pad. Red probe on the anode.

Working, it reads

About 0.5 to 0.8 V anode to cathode, and open the other way. Small switching diodes read about 0.6 to 0.7 V; large rectifiers can read a little lower.

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: failed open.
  • A reading the wrong way round as well: 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 three-pin body can hold two diodes. With a common pin they read two junctions from that pin, just like a transistor; in series they read two drops end to end. Test each pair the datasheet names.

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.

Printed with a code easy to misread as T1

One character differs, and it is one that is easy to confuse under a lamp. Each code has a page of its own.

Codes that begin with T1

For a marking with its end worn or burnt off. Each code has a page of its own.

Open this in the search to correct a character or try another package.