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SMD code 3Es

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, s, is lower case, which on NXP and Philips parts is a date or factory code, so it was set aside and 3E was searched.

109 parts are printed 3Es

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.

  • CM9NB857ASOT-23PNP transistor, 3 pins, Canaan MicroelectronicsPNP transistorSOT-233 pinsCanaan Microelectronics
    What it is
    PNP transistor
    Maker
    Canaan Microelectronics
    Package
    SOT-23
    Pins
    3
    Details
    PNP transistor: AF, Sw, 50V, 100mA, 200mW, B=110..220, 100MHz
    Source
    Published code list

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

  • CM9NB857AWSOT-323PNP transistor, 3 pins, Canaan MicroelectronicsPNP transistorSOT-3233 pinsCanaan Microelectronics
    What it is
    PNP transistor
    Maker
    Canaan Microelectronics
    Package
    SOT-323
    Pins
    3
    Details
    PNP transistor: AF, Sw, 50V, 100mA, 150mW, B=110..220, 100MHz
    Source
    Published code list

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

  • CMBTH10SOT-233 pins, CdiNot recordedSOT-233 pinsCdi
    What it is
    Not recorded
    Maker
    Cdi
    Package
    SOT-23
    Pins
    3
    Details
    Si-npn: GP, 30V, 25mA, 225mW, B>60, >650MHz
    Source
    Published code list

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

  • FMMT-A42SOT-233 pins, Diodes IncorporatedNot recordedSOT-233 pinsDiodes Incorporated
    What it is
    Not recorded
    Maker
    Diodes Incorporated
    Package
    SOT-23
    Pins
    3
    Details
    MPSA42
    Source
    Published code list

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

  • FMMTA42SOT-233 pins, Diodes IncorporatedNot recordedSOT-233 pinsDiodes Incorporated
    What it is
    Not recorded
    Maker
    Diodes Incorporated
    Package
    SOT-23
    Pins
    3
    Details
    npn 300V 200mA
    Source
    Published code list

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

  • FMMTA42TASOT-233 pins, Diodes IncorporatedNot recordedSOT-233 pinsDiodes Incorporated
    What it is
    Not recorded
    Maker
    Diodes Incorporated
    Package
    SOT-23
    Pins
    3
    Details
    NPN high voltage transistor
    Source
    Published code list

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

  • FMMTA42TCSOT-233 pins, Diodes IncorporatedNot recordedSOT-233 pinsDiodes Incorporated
    What it is
    Not recorded
    Maker
    Diodes Incorporated
    Package
    SOT-23
    Pins
    3
    Details
    NPN high voltage transistor
    Source
    Published code list

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

  • FS8KSMCRectifier, 2 pins, Fagor ElectronicaRectifierSMC2 pinsFagor Electronica
    What it is
    Rectifier
    Maker
    Fagor Electronica
    Package
    SMC
    Pins
    2
    Details
    Diode: Rectifier, 800V, 8A, Vf<1.2V(8A), 60pF
    Source
    Published code list

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

  • GM857ASOT-23PNP transistor, 3 pins, Guilin Strong Micro ElectronicsPNP transistorSOT-233 pinsGuilin Strong Micro Electronics
    What it is
    PNP transistor
    Maker
    Guilin Strong Micro Electronics
    Package
    SOT-23
    Pins
    3
    Details
    PNP transistor: GP, 50V, 100mA, 310mW, B=110..220, >150MHz
    Source
    Published code list

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

  • HABC857ASOT-23PNP transistor, 3 pins, Hottech ElectronicsPNP transistorSOT-233 pinsHottech Electronics
    What it is
    PNP transistor
    Maker
    Hottech Electronics
    Package
    SOT-23
    Pins
    3
    Details
    PNP transistor: GP, 50V, 100mA, 200mW, >100MHz, B=110..220
    Source
    Published code list

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

  • KST10SOT-233 pins, Fairchild SemiconductorNot recordedSOT-233 pinsFairchild Semiconductor
    What it is
    Not recorded
    Maker
    Fairchild Semiconductor
    Package
    SOT-23
    Pins
    3
    Details
    Si-npn: GP, 30V, 25mA, 330mW, B>60, >650MHz
    Source
    Published code list

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

  • MC100EP16VAMNDFN8 pins, onsemiNot recordedDFN8 pinsonsemi
    What it is
    Not recorded
    Maker
    onsemi
    Package
    DFN
    Pins
    8
    Source
    Published code list

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

  • MM3Z62VSOD-323Zener diode, 2 pins, EIC SemiconductorZener diodeSOD-3232 pinsEIC Semiconductor
    What it is
    Zener diode
    Maker
    EIC Semiconductor
    Package
    SOD-323
    Pins
    2
    Source
    Published code list

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

  • MMBTH10RGSOT-23RF transistor, 3 pins, Fairchild SemiconductorRF transistorSOT-233 pinsFairchild Semiconductor
    What it is
    RF transistor
    Maker
    Fairchild Semiconductor
    Package
    SOT-23
    Pins
    3
    Details
    NPN transistor: RF, 30V, 25mA, 225mW, B>60, >650MHz
    Source
    Published code list

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

  • 1 more part has no package on record
    • IXD5127N23DNRVoltage supervisor, IXYSVoltage supervisorNot recordedNot recordedIXYS
      What it is
      Voltage supervisor
      Maker
      IXYS
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Voltage detector IC: 2.3V±0.8%, -Reset ODO, -MR, 400ms Rt delay
      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

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.

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.

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.

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.

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.

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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