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SMD code G8

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.

4 parts are printed G8

Not sure which one you have?

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

  • BZD27C130PSOD-123FZener diode, 2 pins, Vishay
    What it is
    Zener diode
    Maker
    Vishay
    Package
    SOD-123F
    Pins
    2
    Source
    From the manufacturer's datasheet

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

    Datasheetfor BZD27C130P, opens in a new tab
  • BZT52H-A9V1SOD-123FZener diode, 2 pins, Nexperia
    What it is
    Zener diode
    Maker
    Nexperia
    Package
    SOD-123F
    Pins
    2
    Source
    From the manufacturer's datasheet

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

    Datasheetfor BZT52H-A9V1, opens in a new tab
  • UMG8NSOT-353Digital transistor (NPN, resistors built in), 5 pins, JSCJ
    What it is
    Digital transistor (NPN, resistors built in)
    Maker
    JSCJ
    Package
    SOT-353
    Pins
    5
    Details
    Digital transistor (bias resistors built in), NPN, 100 mA
    Source
    From the manufacturer's datasheet

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

    Datasheetfor UMG8N, opens in a new tab
  • 1 more part has no package on record
    • BZT52C4V7KZener diode, Taiwan Semiconductor
      What it is
      Zener diode
      Maker
      Taiwan Semiconductor
      Package
      Not recorded
      Pins
      Not recorded
      Source
      From the manufacturer's datasheet

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

      Datasheetfor BZT52C4V7K, opens in a new tab

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.

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.

Printed with a code easy to misread as G8

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

Codes that begin with G8

For a marking with its end worn or burnt off. Each code has a page of its own.

Codes not listed here are printed on 95 more parts.

Open this in the search to correct a character or try another package.