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SMD code 1Vt

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.

The last letter, t, is lower case, which on NXP and Philips parts is a date or factory code, so it was set aside and 1V was searched.

45 parts are printed 1Vt

Not sure which one you have?

Answer up to 4 quick questions and these 45 parts are ranked, with a meter test that settles it. It works on a dead part too.

  • BAT54VGPSOT-563Schottky diode, 6 pins, ChenmkoSchottky diodeSOT-5636 pinsChenmko
    What it is
    Schottky diode
    Maker
    Chenmko
    Package
    SOT-563
    Pins
    6
    Details
    SCHOTTKY DIODE, 30 V, 0.2 A
    Source
    Manufacturer datasheet

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

  • LMBT6427LT1GSOT-23NPN transistor, 3 pins, LRCNPN transistorSOT-233 pinsLRC
    What it is
    NPN transistor
    Maker
    LRC
    Package
    SOT-23
    Pins
    3
    Details
    Bipolar transistor, NPN, IC 500 mA, VCEO 40 V
    Source
    Manufacturer datasheet

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

  • MMBT6427SOT-23Darlington transistor, 3 pins, Taitron ComponentsDarlington transistorSOT-233 pinsTaitron Components
    What it is
    Darlington transistor
    Maker
    Taitron Components
    Package
    SOT-23
    Pins
    3
    Source
    Manufacturer datasheet

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

  • MMBT6427LSOT-23NPN transistor, 3 pins, onsemiNPN transistorSOT-233 pinsonsemi
    What it is
    NPN transistor
    Maker
    onsemi
    Package
    SOT-23
    Pins
    3
    Details
    Darlington Transistor
    Source
    Manufacturer datasheet

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

  • S-LMBT6427LT1GSOT-23NPN transistor, 3 pins, LRCNPN transistorSOT-233 pinsLRC
    What it is
    NPN transistor
    Maker
    LRC
    Package
    SOT-23
    Pins
    3
    Details
    Bipolar transistor, NPN, IC 500 mA, VCEO 40 V
    Source
    Manufacturer datasheet

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

  • SMMBT6427LSOT-23NPN transistor, 3 pins, onsemiNPN transistorSOT-233 pinsonsemi
    What it is
    NPN transistor
    Maker
    onsemi
    Package
    SOT-23
    Pins
    3
    Details
    Darlington Transistor
    Source
    Manufacturer datasheet

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

  • 2SD1824-TSOT-3233 pins, PanNot recordedSOT-3233 pinsPan
    What it is
    Not recorded
    Maker
    Pan
    Package
    SOT-323
    Pins
    3
    Details
    Si-npn: AF-Amp, 100V, 50mA, 150mW, 90MHz, B=1000..2000
    Source
    Published code list

    Is it dead? The meter test is below: This part.

  • 2SD2441SOT-893 pins, PanNot recordedSOT-893 pinsPan
    What it is
    Not recorded
    Maker
    Pan
    Package
    SOT-89
    Pins
    3
    Details
    Si-npn: Lo-sat, 10V, 1,5A, 190MHz
    Source
    Published code list

    Is it dead? The meter test is below: This part.

  • BAT54VPTSOT-563Schottky diode, 6 pins, Chenmko EnterpriseSchottky diodeSOT-5636 pinsChenmko Enterprise
    What it is
    Schottky diode
    Maker
    Chenmko Enterprise
    Package
    SOT-563
    Pins
    6
    Details
    Diode: Dual, Schottky barrier, 30V, 200mA, Vf<1V(100mA), 5ns
    Source
    Published code list

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

  • BF820SOT-23NPN transistor, 3 pinsNPN transistorSOT-233 pinsNot recorded
    What it is
    NPN transistor
    Maker
    Not recorded
    Package
    SOT-23
    Pins
    3
    Details
    NPN bipolar transistor
    Source
    Published code list

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

  • BF820SSOT-233 pins, VishayNot recordedSOT-233 pinsVishay
    What it is
    Not recorded
    Maker
    Vishay
    Package
    SOT-23
    Pins
    3
    Source
    Published code list

    Is it dead? The meter test is below: This part.

  • BF820WSOT-3233 pins, PhilipsNot recordedSOT-3233 pinsPhilips
    What it is
    Not recorded
    Maker
    Philips
    Package
    SOT-323
    Pins
    3
    Details
    equivalent BF420
    Source
    Published code list

    Is it dead? The meter test is below: This part.

  • 3 more parts have no package on record
    • SGM819S-FBXUDL6GVoltage supervisor, 6 pins, SG MicroVoltage supervisorNot recorded6 pinsSG Micro
      What it is
      Voltage supervisor
      Maker
      SG Micro
      Package
      Not recorded
      Pins
      6
      Details
      Watchdog Timer Circuit
      Source
      Manufacturer datasheet

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

    • SGM2078-3.3XXDH4GLDO regulator, 4 pins, SG MicroLDO regulatorNot recorded4 pinsSG Micro
      What it is
      LDO regulator
      Maker
      SG Micro
      Package
      Not recorded
      Pins
      4
      Details
      3.3 V output, 300mA, 1.2V Logic, Low Power and Low Dropout RF Linear Regulator
      Source
      Manufacturer datasheet

      Is it dead? The meter test is below: Voltage regulator.

    • SGMNQ32430TUIK6GN-channel MOSFET, 6 pins, SG MicroN-channel MOSFETNot recorded6 pinsSG Micro
      What it is
      N-channel MOSFET
      Maker
      SG Micro
      Package
      Not recorded
      Pins
      6
      Details
      30V, Power, Single N-Channel, DFN Package, MOSFET
      Source
      Manufacturer datasheet

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

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.

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.

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.

Darlington 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 collector and about 1.1 to 1.4 V to the emitter, two junctions in series, and open the other way round. Collector to emitter reads open. Built-in resistors can change these readings.

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.

Darlington 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 collector and about 1.1 to 1.4 V to the emitter, two junctions in series, and open the other way round. Collector to emitter reads open. Built-in resistors can change these readings.

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.

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.

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.

N-channel MOSFET

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

Working, it reads

Red probe on the source, black on the drain: about 0.4 to 0.9 V, the body diode. Open the other way. The gate reads open to both other pins, both ways.

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. Often all three pins end up shorted together.
  • No body diode at all: failed open.
On the board
the gate usually has a resistor to the source, so gate to source reads that resistor, which is not a fault. A drain short can be the load. 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.

This part

Diode range and ohms range, part lifted.

Working, it reads

Depends on what it is. The datasheet, or an identical part, says.

Dead, it reads

  • Between two pins, the same reading both ways, near 0 V with a continuous beep: shorted.
  • Open between every pair of pins: failed open, or a part that reads open when working.
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.

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 1Vt

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

Codes not listed here are printed on 49 more parts.

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