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SMD code 4Cs

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 4C was searched.

100 parts are printed 4Cs

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.

  • BC859CSOT-23Transistor, 3 pins, InfineonTransistorSOT-233 pinsInfineon
    What it is
    Transistor
    Maker
    Infineon
    Package
    SOT-23
    Pins
    3
    Pinout
    • 1 base
    • 2 emitter
    • 3 collector
    Details
    SMD General Purpose PNP Transistors
    Source
    Manufacturer datasheet

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

  • BC859CLSOT-23PNP transistor, 3 pins, onsemiPNP transistorSOT-233 pinsonsemi
    What it is
    PNP transistor
    Maker
    onsemi
    Package
    SOT-23
    Pins
    3
    Details
    General Purpose Transistors Series
    Source
    Manufacturer datasheet

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

  • BC859CWSOT-323Transistor, 3 pins, YFWTransistorSOT-3233 pinsYFW
    What it is
    Transistor
    Maker
    YFW
    Package
    SOT-323
    Pins
    3
    Details
    SMD General Purpose PNP Transistors
    Source
    Manufacturer datasheet

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

  • BZT52C2V4SOD-123FZener diode, 2 pins, DiotecZener diodeSOD-123F2 pinsDiotec
    What it is
    Zener diode
    Maker
    Diotec
    Package
    SOD-123F
    Pins
    2
    Source
    Manufacturer datasheet

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

  • BZT52C17WUSOD-723Zener diode, 2 pins, Taitron ComponentsZener diodeSOD-7232 pinsTaitron Components
    What it is
    Zener diode
    Maker
    Taitron Components
    Package
    SOD-723
    Pins
    2
    Details
    SMD Zener Diodes (Two Terminals) - 200mW
    Source
    Manufacturer datasheet

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

  • BZX384B18SOD-323Zener diode, 2 pins, VishayZener diodeSOD-3232 pinsVishay
    What it is
    Zener diode
    Maker
    Vishay
    Package
    SOD-323
    Pins
    2
    Source
    Manufacturer datasheet

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

  • BZX584C17SOD-523Zener diode, 2 pins, PanjitZener diodeSOD-5232 pinsPanjit
    What it is
    Zener diode
    Maker
    Panjit
    Package
    SOD-523
    Pins
    2
    Source
    Manufacturer datasheet

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

  • BZX584C17-AUSOD-523Zener diode, 2 pins, PanjitZener diodeSOD-5232 pinsPanjit
    What it is
    Zener diode
    Maker
    Panjit
    Package
    SOD-523
    Pins
    2
    Source
    Manufacturer datasheet

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

  • DLC24CSOD-323ESD protection diode, 2 pins, Galaxy MicroelectronicsESD protection diodeSOD-3232 pinsGalaxy Microelectronics
    What it is
    ESD protection diode
    Maker
    Galaxy Microelectronics
    Package
    SOD-323
    Pins
    2
    Details
    24V, 350W, Surface Mount TVS
    Source
    Manufacturer datasheet

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

  • DLC24CWSOD-123ESD protection diode, 2 pins, Galaxy MicroelectronicsESD protection diodeSOD-1232 pinsGalaxy Microelectronics
    What it is
    ESD protection diode
    Maker
    Galaxy Microelectronics
    Package
    SOD-123
    Pins
    2
    Details
    24V, 350W, Surface Mount TVS
    Source
    Manufacturer datasheet

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

  • GBLC24CSOD-323ESD protection diode, 2 pins, ProTek DevicesESD protection diodeSOD-3232 pinsProTek Devices
    What it is
    ESD protection diode
    Maker
    ProTek Devices
    Package
    SOD-323
    Pins
    2
    Details
    Ultra Low Capacitance TVS Array
    Source
    Manufacturer datasheet

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

  • LESD8D24CT5GSOD-882ESD protection diode, 2 pins, LRCESD protection diodeSOD-8822 pinsLRC
    What it is
    ESD protection diode
    Maker
    LRC
    Package
    SOD-882
    Pins
    2
    Details
    ESD protection diode, VRWM 25 V, IR @VRWM 0.1 μA, VBR Min 26 V
    Source
    Manufacturer datasheet

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

  • MM1Z 2V4SOD-123Zener diode, 2 pins, HottechZener diodeSOD-1232 pinsHottech
    What it is
    Zener diode
    Maker
    Hottech
    Package
    SOD-123
    Pins
    2
    Details
    Zener diode, VZ 2.4 V
    Source
    Manufacturer datasheet

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

  • 2 more parts have no package on record

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.

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.

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.

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.

Printed with a code easy to misread as 4Cs

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 38 more parts.

Did you find your part?

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