SMD code T4-
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.
160 parts are printed T4-
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.
BAV16WSSOD-323Switching diode, 2 pins, Diodes IncorporatedSwitching diodeSOD-3232 pinsDiodes Incorporated
- What it is
- Switching diode
- Maker
- Diodes Incorporated
- Package
- SOD-323
- Pins
- 2
- Pinout
- 1 cathode
- 2 anode
- Details
- Surface-mount fast switching diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
BZX84-C2V7SOT-23Zener diode, 3 pins, NexperiaZener diodeSOT-233 pinsNexperia
- What it is
- Zener diode
- Maker
- Nexperia
- Package
- SOT-23
- Pins
- 3
- Pinout
- 1 anode
- 2 not connected
- 3 cathode
- Details
- 2.7 V approx. ±5% voltage regulator (Zener) diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
BZX384-C2V7SOD-323Zener diode, 2 pins, NexperiaZener diodeSOD-3232 pinsNexperia
- What it is
- Zener diode
- Maker
- Nexperia
- Package
- SOD-323
- Pins
- 2
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
CDBMS240-HFSOD-123FSchottky diode, 2 pins, ComchipSchottky diodeSOD-123F2 pinsComchip
- What it is
- Schottky diode
- Maker
- Comchip
- Package
- SOD-123F
- Pins
- 2
- Details
- 40 V, 2 A Schottky barrier diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
CDST-6100-HFSOT-23Switching diode, 3 pins, ComchipSwitching diodeSOT-233 pinsComchip
- What it is
- Switching diode
- Maker
- Comchip
- Package
- SOT-23
- Pins
- 3
- Details
- 70 V, 200 mA switching diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
H1N4148WSE308SOD-323Switching diode, 2 pins, HXYSwitching diodeSOD-3232 pinsHXY
- What it is
- Switching diode
- Maker
- HXY
- Package
- SOD-323
- Pins
- 2
- Details
- Switching diode, 100 V, 0.15 A
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
H1SS355TE-17SOD-323Switching diode, 2 pins, HXYSwitching diodeSOD-3232 pinsHXY
- What it is
- Switching diode
- Maker
- HXY
- Package
- SOD-323
- Pins
- 2
- Details
- Switching diode, 100 V, 0.15 A
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
H1SS400SMT2RSOD-523Switching diode, 2 pins, HXYSwitching diodeSOD-5232 pinsHXY
- What it is
- Switching diode
- Maker
- HXY
- Package
- SOD-523
- Pins
- 2
- Details
- Switching diode, 100 V, 0.15 A
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
HL1N4148WT1GSOD-123Switching diode, 2 pins, HXYSwitching diodeSOD-1232 pinsHXY
- What it is
- Switching diode
- Maker
- HXY
- Package
- SOD-123
- Pins
- 2
- Details
- Switching diode, 100 V, 0.3 A
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
HMMSD4148T1GSOD-123Switching diode, 2 pins, HXYSwitching diodeSOD-1232 pinsHXY
- What it is
- Switching diode
- Maker
- HXY
- Package
- SOD-123
- Pins
- 2
- Details
- Switching diode, 100 V, 0.3 A
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
HSMMSD4148T1GSOD-123Switching diode, 2 pins, HXYSwitching diodeSOD-1232 pinsHXY
- What it is
- Switching diode
- Maker
- HXY
- Package
- SOD-123
- Pins
- 2
- Details
- Switching diode, 100 V, 0.3 A
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
L1N4148FT1GSOD-123FSwitching diode, 2 pins, LRCSwitching diodeSOD-123F2 pinsLRC
- What it is
- Switching diode
- Maker
- LRC
- Package
- SOD-123F
- Pins
- 2
- Details
- Switching diode, VR 75 V, IF 150 mA, VF Max 1.25 V
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
L1N4148WT1GSOD-123Switching diode, 2 pins, HXYSwitching diodeSOD-1232 pinsHXY
- What it is
- Switching diode
- Maker
- HXY
- Package
- SOD-123
- Pins
- 2
- Details
- Switching diode, 100 V, 0.3 A
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
LNTK2575LT1GSOT-23N-channel MOSFET, 3 pins, LRCN-channel MOSFETSOT-233 pinsLRC
- What it is
- N-channel MOSFET
- Maker
- LRC
- Package
- SOT-23
- Pins
- 3
- Details
- MOSFET, N-Channel(with ESD), VDSS 25 V, VGS 8 V
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: N-channel MOSFET.
1 more part has no package on record
CD4148WSNSwitching diode, LeiditechSwitching diodeNot recordedNot recordedLeiditech
- What it is
- Switching diode
- Maker
- Leiditech
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Switching diode, 100 V
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon 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.
Silicon diode
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
- 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.
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.
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.
N-channel MOSFET
Diode range, part lifted. Test drain to source first, then short gate to source and test again.
Working, it reads
Red probe on the source, black on the drain: about 0.4 to 0.9 V, the body diode. Open the other way. The gate reads open to both other pins, both ways.
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. Often all three pins end up shorted together.
- No body diode at all: failed open.
- On the board
- the gate usually has a resistor to the source, so gate to source reads that resistor, which is not a fault. A drain short can be the load. 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.
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