SMD marking

T4in SOT-23

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.

3 parts are printed T4

Not sure which one you have?

Answer up to 4 quick questions and these 3 parts are ranked, with a meter test that settles it. It works on a dead part too.

BZX84-C2V7SOT-23Zener diode, 3 pins, NexperiaZener diode3 pinsNexperia
What it is
Zener diode
Maker
Nexperia
Package
SOT-23
Pins
3
Details
2.7 V approx. ±5% voltage regulator (Zener) diode
Source
From the manufacturer's datasheet
Is it dead?
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:
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.
Datasheetfor BZX84-C2V7, opens in a new tab
2 more parts have no package on record. Nothing rules them out, so they stay.
- 1N4148WPSwitching diode, DiotecSwitching diodeNot recordedDiotec
  What it is
  Switching diode
  Maker
  Diotec
  Package
  Not recorded
  Pins
  Not recorded
  Details
  SMD Small Signal Switching Diodes
  Source
  From the manufacturer's datasheet
  Is it dead?
  Diode range, part lifted or one leg off the pad. Red probe on the anode.
  Working, it reads
  About 0.5 to 0.8 V anode to cathode, and open the other way. Small switching diodes read about 0.6 to 0.7 V; large rectifiers can read a little lower.
  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: failed open.
  A reading the wrong way round as well: leaky.
  On the board:
  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 three-pin body can hold two diodes. With a common pin they read two junctions from that pin, just like a transistor; in series they read two drops end to end. Test each pair the datasheet names.
  A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
  Datasheetfor 1N4148WP, opens in a new tab
- 1N4148WTHSwitching diode, Taiwan SemiconductorSwitching diodeNot recordedTaiwan Semiconductor
  What it is
  Switching diode
  Maker
  Taiwan Semiconductor
  Package
  Not recorded
  Pins
  Not recorded
  Source
  From the manufacturer's datasheet
  Is it dead?
  Diode range, part lifted or one leg off the pad. Red probe on the anode.
  Working, it reads
  About 0.5 to 0.8 V anode to cathode, and open the other way. Small switching diodes read about 0.6 to 0.7 V; large rectifiers can read a little lower.
  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: failed open.
  A reading the wrong way round as well: leaky.
  On the board:
  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 three-pin body can hold two diodes. With a common pin they read two junctions from that pin, just like a transistor; in series they read two drops end to end. Test each pair the datasheet names.
  A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
  Datasheetfor 1N4148WTH, opens in a new tab

4 more parts are printed with a code easy to misread as T4

Printed with a code easy to misread

One character differs, and it is one that is easy to confuse under a lamp. The odd one out is marked on each.

BAS70-04printed 74SOT-23Schottky diode, 3 pins, NexperiaSchottky diode3 pinsNexperia
Printed 74 on the part. Easy to misread as T4. Check that character with a loupe before you order anything.
What it is
Schottky diode
Maker
Nexperia
Package
SOT-23
Pins
3
Details
SMD Small Signal Schottky Diodes
Source
From the manufacturer's datasheet
Is it dead?
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:
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.
Datasheetfor BAS70-04, opens in a new tab
BZX84-B24printed 74SOT-23Zener diode, 3 pins, NexperiaZener diode3 pinsNexperia
Printed 74 on the part. Easy to misread as T4. Check that character with a loupe before you order anything.
What it is
Zener diode
Maker
Nexperia
Package
SOT-23
Pins
3
Details
24 V ±2% voltage regulator (Zener) diode
Source
From the manufacturer's datasheet
Is it dead?
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:
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.
Datasheetfor BZX84-B24, opens in a new tab
2 more parts have no package on record. Nothing rules them out, so they stay.
- SN74LVC2G74DCUprinted 74Flip-flop, 8 pins, Texas InstrumentsFlip-flop8 pinsTexas Instruments
  Printed 74 on the part. Easy to misread as T4. Check that character with a loupe before you order anything.
  What it is
  Flip-flop
  Maker
  Texas Instruments
  Package
  Not recorded
  Pins
  8
  Details
  Single Positive-Edge-Triggered D-Type Flip-Flop With Clear and Preset
  Source
  From the manufacturer's datasheet
  Is it dead?
  Voltage with the board powered; ohms from each pin to ground with it off.
  Working, it reads
  Supply pin at its voltage and the output doing what the datasheet says. Readings between pins depend on the part.
  Dead, it reads
  A pin near 0 Ω to ground or to the supply pin where an identical part does not read that: failed short.
  Supply present, output stuck: failed, or its load has.
  On the board:
  A pin shorted to ground on the board can be anything on that net. Lift the pin to be sure.
  Compare:
  The surest reference is the same IC on a working board, measured pin by pin.
  Watch for:
  Its protection diodes can read like junctions between pins, even like a transistor. That proves nothing either way.
  A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
  Datasheetfor SN74LVC2G74DCU, opens in a new tab
- VSKY1540C9printed 74Schottky diode, VishaySchottky diodeNot recordedVishay
  Printed 74 on the part. Easy to misread as T4. Check that character with a loupe before you order anything.
  What it is
  Schottky diode
  Maker
  Vishay
  Package
  Not recorded
  Pins
  Not recorded
  Details
  74
  Source
  From the manufacturer's datasheet
  Is it dead?
  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:
  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.
  Datasheetfor VSKY1540C9, opens in a new tab

19 more parts have codes that begin with T4

Codes that begin with T4

For a marking with its end worn or burnt off. Each one shows its full printed code.

TL432ACDBZprinted T4B3SOT-23Voltage reference, 3 pins, Texas InstrumentsVoltage reference3 pinsTexas Instruments
Printed T4B3. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.
What it is
Voltage reference
Maker
Texas Instruments
Package
SOT-23
Pins
3
Details
Precision Programmable Reference
Source
From the manufacturer's datasheet
Is it dead?
Voltage with the board powered; ohms from each pin to ground with it off.
Working, it reads
Supply pin at its voltage and the output doing what the datasheet says. Readings between pins depend on the part.
Dead, it reads
A pin near 0 Ω to ground or to the supply pin where an identical part does not read that: failed short.
Supply present, output stuck: failed, or its load has.
On the board:
A pin shorted to ground on the board can be anything on that net. Lift the pin to be sure.
Compare:
The surest reference is the same IC on a working board, measured pin by pin.
Watch for:
Its protection diodes can read like junctions between pins, even like a transistor. That proves nothing either way.
A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
Datasheetfor TL432ACDBZ, opens in a new tab
TL432AIDBZprinted T4A3SOT-23Voltage reference, 3 pins, Texas InstrumentsVoltage reference3 pinsTexas Instruments
Printed T4A3. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.
What it is
Voltage reference
Maker
Texas Instruments
Package
SOT-23
Pins
3
Details
Precision Programmable Reference
Source
From the manufacturer's datasheet
Is it dead?
Voltage with the board powered; ohms from each pin to ground with it off.
Working, it reads
Supply pin at its voltage and the output doing what the datasheet says. Readings between pins depend on the part.
Dead, it reads
A pin near 0 Ω to ground or to the supply pin where an identical part does not read that: failed short.
Supply present, output stuck: failed, or its load has.
On the board:
A pin shorted to ground on the board can be anything on that net. Lift the pin to be sure.
Compare:
The surest reference is the same IC on a working board, measured pin by pin.
Watch for:
Its protection diodes can read like junctions between pins, even like a transistor. That proves nothing either way.
A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
Datasheetfor TL432AIDBZ, opens in a new tab
TL432AQDBZprinted T4D3SOT-23Voltage reference, 3 pins, Texas InstrumentsVoltage reference3 pinsTexas Instruments
Printed T4D3. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.
What it is
Voltage reference
Maker
Texas Instruments
Package
SOT-23
Pins
3
Details
Precision Programmable Reference
Source
From the manufacturer's datasheet
Is it dead?
Voltage with the board powered; ohms from each pin to ground with it off.
Working, it reads
Supply pin at its voltage and the output doing what the datasheet says. Readings between pins depend on the part.
Dead, it reads
A pin near 0 Ω to ground or to the supply pin where an identical part does not read that: failed short.
Supply present, output stuck: failed, or its load has.
On the board:
A pin shorted to ground on the board can be anything on that net. Lift the pin to be sure.
Compare:
The surest reference is the same IC on a working board, measured pin by pin.
Watch for:
Its protection diodes can read like junctions between pins, even like a transistor. That proves nothing either way.
A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
Datasheetfor TL432AQDBZ, opens in a new tab
TL432BIDBZprinted T4F3SOT-23Voltage reference, 3 pins, Texas InstrumentsVoltage reference3 pinsTexas Instruments
Printed T4F3. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.
What it is
Voltage reference
Maker
Texas Instruments
Package
SOT-23
Pins
3
Details
Precision Programmable Reference
Source
From the manufacturer's datasheet
Is it dead?
Voltage with the board powered; ohms from each pin to ground with it off.
Working, it reads
Supply pin at its voltage and the output doing what the datasheet says. Readings between pins depend on the part.
Dead, it reads
A pin near 0 Ω to ground or to the supply pin where an identical part does not read that: failed short.
Supply present, output stuck: failed, or its load has.
On the board:
A pin shorted to ground on the board can be anything on that net. Lift the pin to be sure.
Compare:
The surest reference is the same IC on a working board, measured pin by pin.
Watch for:
Its protection diodes can read like junctions between pins, even like a transistor. That proves nothing either way.
A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
Datasheetfor TL432BIDBZ, opens in a new tab
TL432BQDBZprinted T4H3SOT-23Voltage reference, 3 pins, Texas InstrumentsVoltage reference3 pinsTexas Instruments
Printed T4H3. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.
What it is
Voltage reference
Maker
Texas Instruments
Package
SOT-23
Pins
3
Details
Precision Programmable Reference
Source
From the manufacturer's datasheet
Is it dead?
Voltage with the board powered; ohms from each pin to ground with it off.
Working, it reads
Supply pin at its voltage and the output doing what the datasheet says. Readings between pins depend on the part.
Dead, it reads
A pin near 0 Ω to ground or to the supply pin where an identical part does not read that: failed short.
Supply present, output stuck: failed, or its load has.
On the board:
A pin shorted to ground on the board can be anything on that net. Lift the pin to be sure.
Compare:
The surest reference is the same IC on a working board, measured pin by pin.
Watch for:
Its protection diodes can read like junctions between pins, even like a transistor. That proves nothing either way.
A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
Datasheetfor TL432BQDBZ, opens in a new tab
TL432CDBZprinted T4CSSOT-23Voltage reference, 3 pins, Texas InstrumentsVoltage reference3 pinsTexas Instruments
Printed T4CS. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.
What it is
Voltage reference
Maker
Texas Instruments
Package
SOT-23
Pins
3
Details
Precision Programmable Reference
Source
From the manufacturer's datasheet
Is it dead?
Voltage with the board powered; ohms from each pin to ground with it off.
Working, it reads
Supply pin at its voltage and the output doing what the datasheet says. Readings between pins depend on the part.
Dead, it reads
A pin near 0 Ω to ground or to the supply pin where an identical part does not read that: failed short.
Supply present, output stuck: failed, or its load has.
On the board:
A pin shorted to ground on the board can be anything on that net. Lift the pin to be sure.
Compare:
The surest reference is the same IC on a working board, measured pin by pin.
Watch for:
Its protection diodes can read like junctions between pins, even like a transistor. That proves nothing either way.
A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
Datasheetfor TL432CDBZ, opens in a new tab
TL432IDBZprinted T4ISSOT-23Voltage reference, 3 pins, Texas InstrumentsVoltage reference3 pinsTexas Instruments
Printed T4IS. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.
What it is
Voltage reference
Maker
Texas Instruments
Package
SOT-23
Pins
3
Details
Precision Programmable Reference
Source
From the manufacturer's datasheet
Is it dead?
Voltage with the board powered; ohms from each pin to ground with it off.
Working, it reads
Supply pin at its voltage and the output doing what the datasheet says. Readings between pins depend on the part.
Dead, it reads
A pin near 0 Ω to ground or to the supply pin where an identical part does not read that: failed short.
Supply present, output stuck: failed, or its load has.
On the board:
A pin shorted to ground on the board can be anything on that net. Lift the pin to be sure.
Compare:
The surest reference is the same IC on a working board, measured pin by pin.
Watch for:
Its protection diodes can read like junctions between pins, even like a transistor. That proves nothing either way.
A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
Datasheetfor TL432IDBZ, opens in a new tab
TL432QDBZprinted T4QSSOT-23Voltage reference, 3 pins, Texas InstrumentsVoltage reference3 pinsTexas Instruments
Printed T4QS. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.
What it is
Voltage reference
Maker
Texas Instruments
Package
SOT-23
Pins
3
Details
Precision Programmable Reference
Source
From the manufacturer's datasheet
Is it dead?
Voltage with the board powered; ohms from each pin to ground with it off.
Working, it reads
Supply pin at its voltage and the output doing what the datasheet says. Readings between pins depend on the part.
Dead, it reads
A pin near 0 Ω to ground or to the supply pin where an identical part does not read that: failed short.
Supply present, output stuck: failed, or its load has.
On the board:
A pin shorted to ground on the board can be anything on that net. Lift the pin to be sure.
Compare:
The surest reference is the same IC on a working board, measured pin by pin.
Watch for:
Its protection diodes can read like junctions between pins, even like a transistor. That proves nothing either way.
A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
Datasheetfor TL432QDBZ, opens in a new tab
BAS70-04-Gprinted 74GSOT-23Schottky diode, 3 pins, VishaySchottky diode3 pinsVishay
Printed 74G. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.
What it is
Schottky diode
Maker
Vishay
Package
SOT-23
Pins
3
Details
Small Signal Schottky Diodes, Single and Dual
Source
From the manufacturer's datasheet
Is it dead?
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:
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.
Datasheetfor BAS70-04-G, opens in a new tab
10 more parts have no package on record. Nothing rules them out, so they stay.
- PJSD12printed T4SESD protection diode, PanjitESD protection diodeNot recordedPanjit
  Printed T4S. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.
  What it is
  ESD protection diode
  Maker
  Panjit
  Package
  Not recorded
  Pins
  Not recorded
  Source
  From the manufacturer's datasheet
  Is it dead?
  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:
  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.
  Datasheetfor PJSD12, opens in a new tab
- AON7404Gprinted 7404GMOSFET, Alpha & Omega SemiconductorMOSFETNot recordedAlpha & Omega Semiconductor
  Printed 7404G. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.
  What it is
  MOSFET
  Maker
  Alpha & Omega Semiconductor
  Package
  Not recorded
  Pins
  Not recorded
  Details
  Low-voltage (12-30 V) MOSFET
  Source
  From the manufacturer's datasheet
  Is it dead?
  Diode range, part lifted. Test drain to source first, then short gate to source and test again.
  Working, it reads
  One way between drain and source reads about 0.4 to 0.9 V, the body diode, and the other way open. The gate reads open to both other pins.
  Dead, it reads
  Drain to source the same both ways, near 0 V with a continuous beep, and still so after shorting gate to source: shorted. The classic failure.
  The gate reads low to source or drain: gate shorted.
  No body diode at all: failed open.
  On the board:
  On the board the gate usually has a resistor to the source, which reads as that resistor and is not a fault. Lift a leg to be sure.
  Compare:
  If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.
  Watch for:
  The diode range can charge the gate enough to turn the part on, and then drain to source reads near 0 both ways on a good part. Short gate to source and test again before you condemn it.
  A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
  Datasheetfor AON7404G, opens in a new tab
- AON7422Gprinted 7422GMOSFET, Alpha & Omega SemiconductorMOSFETNot recordedAlpha & Omega Semiconductor
  Printed 7422G. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.
  What it is
  MOSFET
  Maker
  Alpha & Omega Semiconductor
  Package
  Not recorded
  Pins
  Not recorded
  Details
  Low-voltage (12-30 V) MOSFET
  Source
  From the manufacturer's datasheet
  Is it dead?
  Diode range, part lifted. Test drain to source first, then short gate to source and test again.
  Working, it reads
  One way between drain and source reads about 0.4 to 0.9 V, the body diode, and the other way open. The gate reads open to both other pins.
  Dead, it reads
  Drain to source the same both ways, near 0 V with a continuous beep, and still so after shorting gate to source: shorted. The classic failure.
  The gate reads low to source or drain: gate shorted.
  No body diode at all: failed open.
  On the board:
  On the board the gate usually has a resistor to the source, which reads as that resistor and is not a fault. Lift a leg to be sure.
  Compare:
  If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.
  Watch for:
  The diode range can charge the gate enough to turn the part on, and then drain to source reads near 0 both ways on a good part. Short gate to source and test again before you condemn it.
  A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
  Datasheetfor AON7422G, opens in a new tab
- AON7428printed 7428MOSFET, Alpha & Omega SemiconductorMOSFETNot recordedAlpha & Omega Semiconductor
  Printed 7428. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.
  What it is
  MOSFET
  Maker
  Alpha & Omega Semiconductor
  Package
  Not recorded
  Pins
  Not recorded
  Details
  Low-voltage (12-30 V) MOSFET
  Source
  From the manufacturer's datasheet
  Is it dead?
  Diode range, part lifted. Test drain to source first, then short gate to source and test again.
  Working, it reads
  One way between drain and source reads about 0.4 to 0.9 V, the body diode, and the other way open. The gate reads open to both other pins.
  Dead, it reads
  Drain to source the same both ways, near 0 V with a continuous beep, and still so after shorting gate to source: shorted. The classic failure.
  The gate reads low to source or drain: gate shorted.
  No body diode at all: failed open.
  On the board:
  On the board the gate usually has a resistor to the source, which reads as that resistor and is not a fault. Lift a leg to be sure.
  Compare:
  If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.
  Watch for:
  The diode range can charge the gate enough to turn the part on, and then drain to source reads near 0 both ways on a good part. Short gate to source and test again before you condemn it.
  A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
  Datasheetfor AON7428, opens in a new tab
- AON7440printed 7440MOSFET, Alpha & Omega SemiconductorMOSFETNot recordedAlpha & Omega Semiconductor
  Printed 7440. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.
  What it is
  MOSFET
  Maker
  Alpha & Omega Semiconductor
  Package
  Not recorded
  Pins
  Not recorded
  Details
  Low-voltage (12-30 V) MOSFET
  Source
  From the manufacturer's datasheet
  Is it dead?
  Diode range, part lifted. Test drain to source first, then short gate to source and test again.
  Working, it reads
  One way between drain and source reads about 0.4 to 0.9 V, the body diode, and the other way open. The gate reads open to both other pins.
  Dead, it reads
  Drain to source the same both ways, near 0 V with a continuous beep, and still so after shorting gate to source: shorted. The classic failure.
  The gate reads low to source or drain: gate shorted.
  No body diode at all: failed open.
  On the board:
  On the board the gate usually has a resistor to the source, which reads as that resistor and is not a fault. Lift a leg to be sure.
  Compare:
  If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.
  Watch for:
  The diode range can charge the gate enough to turn the part on, and then drain to source reads near 0 both ways on a good part. Short gate to source and test again before you condemn it.
  A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
  Datasheetfor AON7440, opens in a new tab
- AON7442printed 7442MOSFET, Alpha & Omega SemiconductorMOSFETNot recordedAlpha & Omega Semiconductor
  Printed 7442. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.
  What it is
  MOSFET
  Maker
  Alpha & Omega Semiconductor
  Package
  Not recorded
  Pins
  Not recorded
  Details
  Low-voltage (12-30 V) MOSFET
  Source
  From the manufacturer's datasheet
  Is it dead?
  Diode range, part lifted. Test drain to source first, then short gate to source and test again.
  Working, it reads
  One way between drain and source reads about 0.4 to 0.9 V, the body diode, and the other way open. The gate reads open to both other pins.
  Dead, it reads
  Drain to source the same both ways, near 0 V with a continuous beep, and still so after shorting gate to source: shorted. The classic failure.
  The gate reads low to source or drain: gate shorted.
  No body diode at all: failed open.
  On the board:
  On the board the gate usually has a resistor to the source, which reads as that resistor and is not a fault. Lift a leg to be sure.
  Compare:
  If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.
  Watch for:
  The diode range can charge the gate enough to turn the part on, and then drain to source reads near 0 both ways on a good part. Short gate to source and test again before you condemn it.
  A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
  Datasheetfor AON7442, opens in a new tab
- AON7466printed 7466MOSFET, Alpha & Omega SemiconductorMOSFETNot recordedAlpha & Omega Semiconductor
  Printed 7466. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.
  What it is
  MOSFET
  Maker
  Alpha & Omega Semiconductor
  Package
  Not recorded
  Pins
  Not recorded
  Details
  Low-voltage (12-30 V) MOSFET
  Source
  From the manufacturer's datasheet
  Is it dead?
  Diode range, part lifted. Test drain to source first, then short gate to source and test again.
  Working, it reads
  One way between drain and source reads about 0.4 to 0.9 V, the body diode, and the other way open. The gate reads open to both other pins.
  Dead, it reads
  Drain to source the same both ways, near 0 V with a continuous beep, and still so after shorting gate to source: shorted. The classic failure.
  The gate reads low to source or drain: gate shorted.
  No body diode at all: failed open.
  On the board:
  On the board the gate usually has a resistor to the source, which reads as that resistor and is not a fault. Lift a leg to be sure.
  Compare:
  If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.
  Watch for:
  The diode range can charge the gate enough to turn the part on, and then drain to source reads near 0 both ways on a good part. Short gate to source and test again before you condemn it.
  A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
  Datasheetfor AON7466, opens in a new tab
- AONS74304printed 74304MOSFET, Alpha & Omega SemiconductorMOSFETNot recordedAlpha & Omega Semiconductor
  Printed 74304. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.
  What it is
  MOSFET
  Maker
  Alpha & Omega Semiconductor
  Package
  Not recorded
  Pins
  Not recorded
  Details
  Low-voltage (12-30 V) MOSFET
  Source
  From the manufacturer's datasheet
  Is it dead?
  Diode range, part lifted. Test drain to source first, then short gate to source and test again.
  Working, it reads
  One way between drain and source reads about 0.4 to 0.9 V, the body diode, and the other way open. The gate reads open to both other pins.
  Dead, it reads
  Drain to source the same both ways, near 0 V with a continuous beep, and still so after shorting gate to source: shorted. The classic failure.
  The gate reads low to source or drain: gate shorted.
  No body diode at all: failed open.
  On the board:
  On the board the gate usually has a resistor to the source, which reads as that resistor and is not a fault. Lift a leg to be sure.
  Compare:
  If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.
  Watch for:
  The diode range can charge the gate enough to turn the part on, and then drain to source reads near 0 both ways on a good part. Short gate to source and test again before you condemn it.
  A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
  Datasheetfor AONS74304, opens in a new tab
- AONS74306printed 74306MOSFET, Alpha & Omega SemiconductorMOSFETNot recordedAlpha & Omega Semiconductor
  Printed 74306. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.
  What it is
  MOSFET
  Maker
  Alpha & Omega Semiconductor
  Package
  Not recorded
  Pins
  Not recorded
  Details
  Low-voltage (12-30 V) MOSFET
  Source
  From the manufacturer's datasheet
  Is it dead?
  Diode range, part lifted. Test drain to source first, then short gate to source and test again.
  Working, it reads
  One way between drain and source reads about 0.4 to 0.9 V, the body diode, and the other way open. The gate reads open to both other pins.
  Dead, it reads
  Drain to source the same both ways, near 0 V with a continuous beep, and still so after shorting gate to source: shorted. The classic failure.
  The gate reads low to source or drain: gate shorted.
  No body diode at all: failed open.
  On the board:
  On the board the gate usually has a resistor to the source, which reads as that resistor and is not a fault. Lift a leg to be sure.
  Compare:
  If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.
  Watch for:
  The diode range can charge the gate enough to turn the part on, and then drain to source reads near 0 both ways on a good part. Short gate to source and test again before you condemn it.
  A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
  Datasheetfor AONS74306, opens in a new tab
- AONS74312printed 74312MOSFET, Alpha & Omega SemiconductorMOSFETNot recordedAlpha & Omega Semiconductor
  Printed 74312. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.
  What it is
  MOSFET
  Maker
  Alpha & Omega Semiconductor
  Package
  Not recorded
  Pins
  Not recorded
  Details
  Low-voltage (12-30 V) MOSFET
  Source
  From the manufacturer's datasheet
  Is it dead?
  Diode range, part lifted. Test drain to source first, then short gate to source and test again.
  Working, it reads
  One way between drain and source reads about 0.4 to 0.9 V, the body diode, and the other way open. The gate reads open to both other pins.
  Dead, it reads
  Drain to source the same both ways, near 0 V with a continuous beep, and still so after shorting gate to source: shorted. The classic failure.
  The gate reads low to source or drain: gate shorted.
  No body diode at all: failed open.
  On the board:
  On the board the gate usually has a resistor to the source, which reads as that resistor and is not a fault. Lift a leg to be sure.
  Compare:
  If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.
  Watch for:
  The diode range can charge the gate enough to turn the part on, and then drain to source reads near 0 both ways on a good part. Short gate to source and test again before you condemn it.
  A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
  Datasheetfor AONS74312, opens in a new tab

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

3 parts are printed T4

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Is it dead?

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Printed with a code easy to misread

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Is it dead?

Codes that begin with T4

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Is it dead?

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Is it dead?

Is it dead?

Is it dead?

Is it dead?

Is it dead?

Is it dead?

Is it dead?

Is it dead?

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Is it dead?

Is it dead?

Is it dead?

Is it dead?

Is it dead?