SMD code 4Ct
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, t, is lower case, which on NXP and Philips parts is a date or factory code, so it was set aside and 4C was searched.
107 parts are printed 4Ct
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.
4SMF43CASOD-123FTVS diode, 2 pins, VishayTVS diodeSOD-123F2 pinsVishay
- What it is
- TVS diode
- Maker
- Vishay
- Package
- SOD-123F
- Pins
- 2
- Details
- 400 W TVS diode, bidirectional
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: TVS or ESD protection diode.
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.
2 more parts have no package on record
ESD8104MUESD protection diode, onsemiESD protection diodeNot recordedNot recordedonsemi
- What it is
- ESD protection diode
- Maker
- onsemi
- Package
- Not recorded
- Pins
- Not recorded
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: TVS or ESD protection diode.
GBLC24CDNESD protection diode, ProTek DevicesESD protection diodeNot recordedNot recordedProTek Devices
- What it is
- ESD protection diode
- Maker
- ProTek Devices
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Ultra Low Capacitance TVS
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: TVS or ESD protection diode.
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.
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.
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.
Printed with a code easy to misread as 4Ct
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 16 more parts.
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