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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 and published code lists.

56 parts are printed T1-

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.

  • UMT1NSOT-363Dual PNP transistor, 6 pins, ROHMDual PNP transistorSOT-3636 pinsROHM
    What it is
    Dual PNP transistor
    Maker
    ROHM
    Package
    SOT-363
    Pins
    6
    Details
    50V, 0.15A, General Purpose PNP Bipolar Transistor
    Source
    Manufacturer datasheet

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

  • BTC5181WC3SOT-523NPN transistor, 3 pins, CYStekNPN transistorSOT-5233 pinsCYStek
    What it is
    NPN transistor
    Maker
    CYStek
    Package
    SOT-523
    Pins
    3
    Details
    3 V, 0.01 A NPN transistor
    Source
    Manufacturer datasheet

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

  • 1PS79SB63SOD-323Schottky diode, 2 pins, PhilipsSchottky diodeSOD-3232 pinsPhilips
    What it is
    Schottky diode
    Maker
    Philips
    Package
    SOD-323
    Pins
    2
    Details
    Diode: Schottky, Sw, 5V, 20mA, Vf<0.3V(1mA), <0.5pF
    Source
    Published code list

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

  • AP8822C-11GASOT-23Voltage supervisor, 3 pins, Anwell SemiconductorVoltage supervisorSOT-233 pinsAnwell Semiconductor
    What it is
    Voltage supervisor
    Maker
    Anwell Semiconductor
    Package
    SOT-23
    Pins
    3
    Details
    Voltage detector IC: 1.1V±2%, -Reset PPO, Rdt=200ms, H-free
    Source
    Published code list

    Is it dead? The meter test is below: Integrated circuit.

  • AP8822C-11GTSOT-323Voltage supervisor, 3 pins, Anwell SemiconductorVoltage supervisorSOT-3233 pinsAnwell Semiconductor
    What it is
    Voltage supervisor
    Maker
    Anwell Semiconductor
    Package
    SOT-323
    Pins
    3
    Details
    Voltage detector IC: 1.1V±2%, -Reset PPO, Rdt=200ms, H-free
    Source
    Published code list

    Is it dead? The meter test is below: Integrated circuit.

  • AP8822C-11PASOT-23Voltage supervisor, 3 pins, Anwell SemiconductorVoltage supervisorSOT-233 pinsAnwell Semiconductor
    What it is
    Voltage supervisor
    Maker
    Anwell Semiconductor
    Package
    SOT-23
    Pins
    3
    Details
    Voltage detector IC: 1.1V±2%, -Reset PPO, Rdt=200ms
    Source
    Published code list

    Is it dead? The meter test is below: Integrated circuit.

  • AP8822C-11PTSOT-323Voltage supervisor, 3 pins, Anwell SemiconductorVoltage supervisorSOT-3233 pinsAnwell Semiconductor
    What it is
    Voltage supervisor
    Maker
    Anwell Semiconductor
    Package
    SOT-323
    Pins
    3
    Details
    Voltage detector IC: 1.1V±2%, -Reset PPO, Rdt=200ms
    Source
    Published code list

    Is it dead? The meter test is below: Integrated circuit.

  • BCX17TASOT-233 pins, Diodes IncorporatedNot recordedSOT-233 pinsDiodes Incorporated
    What it is
    Not recorded
    Maker
    Diodes Incorporated
    Package
    SOT-23
    Pins
    3
    Details
    PNP medium power transistor
    Source
    Published code list

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

  • BFG590WSOT-343RF transistor, 4 pins, Philips SemiconductorsRF transistorSOT-3434 pinsPhilips Semiconductors
    What it is
    RF transistor
    Maker
    Philips Semiconductors
    Package
    SOT-343
    Pins
    4
    Details
    NPN transistor: UHF, 20V, 200mA, 400mW, B=60..250, 5GHz
    Source
    Published code list

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

  • BSS63SOT-23MOSFET, 3 pins, onsemiMOSFETSOT-233 pinsonsemi
    What it is
    MOSFET
    Maker
    onsemi
    Package
    SOT-23
    Pins
    3
    Source
    Published code list

    Is it dead? The meter test is below: MOSFET.

  • 5 more parts have no package on record
    • AP8822C-11GIVoltage supervisor, Anwell SemiconductorVoltage supervisorNot recordedNot recordedAnwell Semiconductor
      What it is
      Voltage supervisor
      Maker
      Anwell Semiconductor
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Voltage detector IC: 1.1V±2%, -Reset PPO, 200ms Rt delay, H-free
      Source
      Published code list

      Is it dead? The meter test is below: Integrated circuit.

    • AP8822C-11GSVoltage supervisor, Anwell SemiconductorVoltage supervisorNot recordedNot recordedAnwell Semiconductor
      What it is
      Voltage supervisor
      Maker
      Anwell Semiconductor
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Voltage detector IC: 1.1V±2%, -Reset PPO, 200ms Rt delay, H-free
      Source
      Published code list

      Is it dead? The meter test is below: Integrated circuit.

    • AP8822C-11PIVoltage supervisor, Anwell SemiconductorVoltage supervisorNot recordedNot recordedAnwell Semiconductor
      What it is
      Voltage supervisor
      Maker
      Anwell Semiconductor
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Voltage detector IC: 1.1V±2%, -Reset PPO, 200ms Rt delay
      Source
      Published code list

      Is it dead? The meter test is below: Integrated circuit.

    • AP8822C-11PSVoltage supervisor, Anwell SemiconductorVoltage supervisorNot recordedNot recordedAnwell Semiconductor
      What it is
      Voltage supervisor
      Maker
      Anwell Semiconductor
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Voltage detector IC: 1.1V±2%, -Reset PPO, 200ms Rt delay
      Source
      Published code list

      Is it dead? The meter test is below: Integrated circuit.

    • BD45475GVoltage supervisor, ROHMVoltage supervisorNot recordedNot recordedROHM
      What it is
      Voltage supervisor
      Maker
      ROHM
      Package
      Not recorded
      Pins
      Not recorded
      Details
      CMOS-IC: Voltage Detector 4,7V, -Reset Open drain output, 500ms
      Source
      Published code list

      Is it dead? The meter test is below: Integrated circuit.

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 pair

Diode range, part lifted. Test each transistor on its own pins, as the datasheet's pinout gives them.

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.

NPN transistor

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

Working, it reads

Red 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.

Schottky diode

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

Working, it reads

About 0.15 to 0.45 V anode to cathode, roughly half a silicon diode, and open the other way.

Dead, it reads

  • The same reading both ways round, near 0 V with a continuous beep or the same middling value: shorted.
  • A reading the wrong way round as well: leaky.
  • Open both ways: failed open.
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 large Schottky can read about 0.1 V forward and beep like a short, and leaks a little the wrong way when good, more when warm. It is shorted only if it reads the same both ways. Measure it cold, beside an identical cold one.

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

Integrated circuit

Voltage with the board powered; ohms from each pin to ground with it off.

Working, it reads

Supply pin at its voltage and the output doing what the datasheet says. Readings between pins depend on the part.

Dead, it reads

  • A pin near 0 Ω to ground or to the supply pin where an identical part does not read that: failed short.
  • Supply present, output stuck: failed, or its load has.
On the board:
A pin shorted to ground on the board can be anything on that net. Lift the pin to be sure.
Compare:
The surest reference is the same IC on a working board, measured pin by pin.
Watch for:
Its protection diodes can read like junctions between pins, even like a transistor. That proves nothing either way.

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.

MOSFET

Diode range, part lifted. Test drain to source first, then short gate to source and test again.

Working, it reads

One way between drain and source reads about 0.4 to 0.9 V, the body diode, and the other way open. The gate reads open to both other pins.

Dead, it reads

  • Drain to source the same both ways, near 0 V with a continuous beep, and still so after shorting gate to source: shorted. The classic failure.
  • The gate reads low to source or drain: gate shorted.
  • No body diode at all: failed open.
On the board
the gate usually has a resistor to the source, which reads as that resistor and is not a fault. Lift a leg to be sure.
Compare:
If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.
Watch for:
The diode range can charge the gate enough to turn the part on, and then drain to source reads near 0 both ways on a good part. Short gate to source and test again before you condemn it.

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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