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SMD code Y2p

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, p, is lower case, which on NXP and Philips parts is a date or factory code, so it was set aside and Y2 was searched.

104 parts are printed Y2p

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.

  • BZX584C12SOD-523Zener diode, 2 pins, Galaxy MicroelectronicsZener diodeSOD-5232 pinsGalaxy Microelectronics
    What it is
    Zener diode
    Maker
    Galaxy Microelectronics
    Package
    SOD-523
    Pins
    2
    Source
    Manufacturer datasheet

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

  • BZX584C12-MSSOD-523Zener diode, 2 pins, MSKSEMIZener diodeSOD-5232 pinsMSKSEMI
    What it is
    Zener diode
    Maker
    MSKSEMI
    Package
    SOD-523
    Pins
    2
    Source
    Manufacturer datasheet

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

  • BZX584C12AUSOD-523Zener diode, 2 pins, JieJieZener diodeSOD-5232 pinsJieJie
    What it is
    Zener diode
    Maker
    JieJie
    Package
    SOD-523
    Pins
    2
    Source
    Manufacturer datasheet

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

  • BZX784C30SOD-723Zener diode, 2 pins, SeCoSZener diodeSOD-7232 pinsSeCoS
    What it is
    Zener diode
    Maker
    SeCoS
    Package
    SOD-723
    Pins
    2
    Source
    Manufacturer datasheet

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

  • CZRH584C12-HFSOD-523Zener diode, 2 pins, ComchipZener diodeSOD-5232 pinsComchip
    What it is
    Zener diode
    Maker
    Comchip
    Package
    SOD-523
    Pins
    2
    Details
    12 V 0.2 mW zener diode
    Source
    Manufacturer datasheet

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

  • DMBT8550SOT-23PNP transistor, 3 pins, DC ComponentsPNP transistorSOT-233 pinsDC Components
    What it is
    PNP transistor
    Maker
    DC Components
    Package
    SOT-23
    Pins
    3
    Details
    PNP bipolar transistor
    Source
    Manufacturer datasheet

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

  • FS8550SOT-23NPN transistor, 3 pins, Formosa MicrosemiNPN transistorSOT-233 pinsFormosa Microsemi
    What it is
    NPN transistor
    Maker
    Formosa Microsemi
    Package
    SOT-23
    Pins
    3
    Source
    Manufacturer datasheet

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

  • GSS8550SOT-23PNP transistor, 3 pins, Good-ArkPNP transistorSOT-233 pinsGood-Ark
    What it is
    PNP transistor
    Maker
    Good-Ark
    Package
    SOT-23
    Pins
    3
    Details
    PNP transistor, 25 V, 1.5 A
    Source
    Manufacturer datasheet

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

  • LBZX84C12LT1GSOT-23Zener diode, 3 pins, LRCZener diodeSOT-233 pinsLRC
    What it is
    Zener diode
    Maker
    LRC
    Package
    SOT-23
    Pins
    3
    Details
    Zener diode, VZ Min 11.4 V, VZ Nom 12 V, VZ Max 12.7 V
    Source
    Manufacturer datasheet

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

  • MM3Z36BWSOD-323Zener diode, 2 pins, YFWZener diodeSOD-3232 pinsYFW
    What it is
    Zener diode
    Maker
    YFW
    Package
    SOD-323
    Pins
    2
    Source
    Manufacturer datasheet

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

  • MM5Z12V-CSOD-523Zener diode, 2 pins, SeCoSZener diodeSOD-5232 pinsSeCoS
    What it is
    Zener diode
    Maker
    SeCoS
    Package
    SOD-523
    Pins
    2
    Source
    Manufacturer datasheet

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

  • MMBT1781-RSOT-23NPN transistor, 3 pins, Good-ArkNPN transistorSOT-233 pinsGood-Ark
    What it is
    NPN transistor
    Maker
    Good-Ark
    Package
    SOT-23
    Pins
    3
    Details
    NPN transistor, 32 V, 0.8 A
    Source
    Manufacturer datasheet

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

  • MMBTSD123SOT-23Transistor, 3 pins, YFWTransistorSOT-233 pinsYFW
    What it is
    Transistor
    Maker
    YFW
    Package
    SOT-23
    Pins
    3
    Details
    Bipolar transistor
    Source
    Manufacturer datasheet

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

  • 2 more parts have no package on record
    • KRC836EDigital transistor (NPN, resistors built in), KECDigital transistor (NPN, resistors built in)Not recordedNot recordedKEC
      What it is
      Digital transistor (NPN, resistors built in)
      Maker
      KEC
      Package
      Not recorded
      Pins
      Not recorded
      Source
      Manufacturer datasheet

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

    • KRC836UDigital transistor (NPN, resistors built in), KECDigital transistor (NPN, resistors built in)Not recordedNot recordedKEC
      What it is
      Digital transistor (NPN, resistors built in)
      Maker
      KEC
      Package
      Not recorded
      Pins
      Not recorded
      Source
      Manufacturer datasheet

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

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.

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.

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.

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.

Digital transistor

Ohms range, part lifted. The datasheet gives the built-in resistors: R1 in series with the base, R2 from base to emitter.

Working, it reads

Base to emitter reads about R1 plus R2 either way round, about 20 kΩ on a 10 k and 10 k part, give or take their wide tolerance. Collector to emitter reads open. A part with no R2 reads a junction behind R1 one way instead.

Dead, it reads

  • Collector to emitter the same both ways, near 0 Ω with a continuous beep: shorted.
  • From the base, open or far above R1 plus R2: R1 has failed. Static damage shows here most often.
  • Base to emitter near 0 Ω: failed short.
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:
The readings depend on the resistor values, so an identical part elsewhere on the board is the surest reference. Measure it the same way.
Watch for:
On the diode range a good part with 10 kΩ resistors reads open on every pair, so a good part looks dead there. Use the ohms range.

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.

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