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SMD code G1-

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.

162 parts are printed G1-

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.

  • MMSZ5226BS-FLSOD-323Zener diode, 2 pins, Formosa MicrosemiZener diodeSOD-3232 pinsFormosa Microsemi
    What it is
    Zener diode
    Maker
    Formosa Microsemi
    Package
    SOD-323
    Pins
    2
    Source
    Manufacturer datasheet

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

  • MMSZ5226BS-MSSOD-323Zener diode, 2 pins, MSKSEMIZener diodeSOD-3232 pinsMSKSEMI
    What it is
    Zener diode
    Maker
    MSKSEMI
    Package
    SOD-323
    Pins
    2
    Source
    Manufacturer datasheet

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

  • MMSZ5226BSCR-CSOD-323Zener diode, 2 pins, SeCoSZener diodeSOD-3232 pinsSeCoS
    What it is
    Zener diode
    Maker
    SeCoS
    Package
    SOD-323
    Pins
    2
    Source
    Manufacturer datasheet

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

  • MMSZ5226BT1GSOD-123Zener diode, 2 pins, HXYZener diodeSOD-1232 pinsHXY
    What it is
    Zener diode
    Maker
    HXY
    Package
    SOD-123
    Pins
    2
    Details
    Zener diode, 5.6 V, 0.02 A
    Source
    Manufacturer datasheet

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

  • PESD3V3S1ULSOD-882ESD protection diode, 2 pins, NexperiaESD protection diodeSOD-8822 pinsNexperia
    What it is
    ESD protection diode
    Maker
    Nexperia
    Package
    SOD-882
    Pins
    2
    Details
    Unidirectional ESD protection diode
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: TVS or ESD protection diode.

  • PMBT5551SOT-23NPN transistor, 3 pins, HXYNPN transistorSOT-233 pinsHXY
    What it is
    NPN transistor
    Maker
    HXY
    Package
    SOT-23
    Pins
    3
    Pinout
    • 1 base
    • 2 emitter
    • 3 collector
    Details
    Bipolar transistor, 160 V, 0.6 A
    Source
    Manufacturer datasheet

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

  • PMBT5551,215SOT-23NPN transistor, 3 pins, HXYNPN transistorSOT-233 pinsHXY
    What it is
    NPN transistor
    Maker
    HXY
    Package
    SOT-23
    Pins
    3
    Details
    Bipolar transistor, 160 V, 0.6 A
    Source
    Manufacturer datasheet

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

  • PMEG2005EGWSOD-123Schottky diode, 2 pins, NexperiaSchottky diodeSOD-1232 pinsNexperia
    What it is
    Schottky diode
    Maker
    Nexperia
    Package
    SOD-123
    Pins
    2
    Details
    20 V, 0.5 A low VF MEGA Schottky barrier rectifier
    Source
    Manufacturer datasheet

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

  • PT23T5551SOT-233 pins, PrisemiNot recordedSOT-233 pinsPrisemi
    What it is
    Not recorded
    Maker
    Prisemi
    Package
    SOT-23
    Pins
    3
    Details
    Bipolar transistor, 160 V, 0.6 A
    Source
    Manufacturer datasheet

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

  • PZT5551SOT-223NPN transistor, 4 pins, Galaxy MicroelectronicsNPN transistorSOT-2234 pinsGalaxy Microelectronics
    What it is
    NPN transistor
    Maker
    Galaxy Microelectronics
    Package
    SOT-223
    Pins
    4
    Details
    160V, 0.6A, General Purpose NPN Bipolar Transistor
    Source
    Manufacturer datasheet

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

  • RB168LAM-30SOD-128Schottky diode, 2 pins, ROHMSchottky diodeSOD-1282 pinsROHM
    What it is
    Schottky diode
    Maker
    ROHM
    Package
    SOD-128
    Pins
    2
    Details
    Schottky Barrier Diode
    Source
    Manufacturer datasheet

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

  • RB168LAM-30TFSOD-128Schottky diode, 2 pins, ROHMSchottky diodeSOD-1282 pinsROHM
    What it is
    Schottky diode
    Maker
    ROHM
    Package
    SOD-128
    Pins
    2
    Details
    Schottky Barrier Diode (AEC-Q101 qualified)
    Source
    Manufacturer datasheet

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

  • S-LMBT5551DW1T1GSOT-363Transistor, 6 pins, LRCTransistorSOT-3636 pinsLRC
    What it is
    Transistor
    Maker
    LRC
    Package
    SOT-363
    Pins
    6
    Details
    Bipolar transistor, N+N, IC 600 mA, VCEO 140 V
    Source
    Manufacturer datasheet

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

  • S-LMBT5551LT1GSOT-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 600 mA, VCEO 160 V
    Source
    Manufacturer datasheet

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

  • SMMBT5551LSOT-23NPN transistor, 3 pins, onsemiNPN transistorSOT-233 pinsonsemi
    What it is
    NPN transistor
    Maker
    onsemi
    Package
    SOT-23
    Pins
    3
    Details
    High Voltage Transistors
    Source
    Manufacturer datasheet

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

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.

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.

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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