SMD code BT
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.
11 parts are printed BT
Not sure which one you have?
Answer up to 4 quick questions and these 11 parts are ranked, with a meter test that settles it. It works on a dead part too.
AO3454SOT-23MOSFET, 3 pins, Alpha & Omega SemiconductorMOSFETSOT-233 pinsAlpha & Omega Semiconductor
- What it is
- MOSFET
- Maker
- Alpha & Omega Semiconductor
- Package
- SOT-23
- Pins
- 3
- Details
- Low-voltage (12-30 V) MOSFET
- Source
- From the manufacturer's datasheet
Is it dead? The meter test is below: MOSFET.
BZT52H-C24SOD-123FZener diode, 2 pins, NexperiaZener diodeSOD-123F2 pinsNexperia
- 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.
SMAJ18ASMATVS diode, 2 pins, VishayTVS diodeSMA2 pinsVishay
- What it is
- TVS diode
- Maker
- Vishay
- Package
- SMA
- Pins
- 2
- Details
- 400 W TVS diode, unidirectional
- Source
- From the manufacturer's datasheet
Is it dead? The meter test is below: TVS or ESD protection diode.
SMBJ18CASMBTVS diode, 2 pins, VishayTVS diodeSMB2 pinsVishay
- What it is
- TVS diode
- Maker
- Vishay
- Package
- SMB
- Pins
- 2
- Details
- 600 W TVS diode, bidirectional
- Source
- From the manufacturer's datasheet
Is it dead? The meter test is below: TVS or ESD protection diode.
SMF18ASOD-123FTVS diode, 2 pins, VishayTVS diodeSOD-123F2 pinsVishay
- What it is
- TVS diode
- Maker
- Vishay
- Package
- SOD-123F
- Pins
- 2
- Details
- SMD Transient Voltage Suppressor Diodes
- Source
- From the manufacturer's datasheet
Is it dead? The meter test is below: TVS or ESD protection diode.
6 more parts have no package on record
AOZ8906CIESD protection diode, Alpha & Omega SemiconductorESD protection diodeNot recordedNot recordedAlpha & Omega Semiconductor
- What it is
- ESD protection diode
- Maker
- Alpha & Omega Semiconductor
- Package
- Not recorded
- Pins
- Not recorded
- Details
- ESD protection for high-speed interfaces
- Source
- From the manufacturer's datasheet
Is it dead? The meter test is below: TVS or ESD protection diode.
BGA619RF amplifier (MMIC), InfineonRF amplifier (MMIC)Not recordedNot recordedInfineon
- What it is
- RF amplifier (MMIC)
- Maker
- Infineon
- Package
- Not recorded
- Pins
- Not recorded
- Source
- From the manufacturer's datasheet
Is it dead? The meter test is below: RF amplifier.
BZX884B68LZener diode, VishayZener diodeNot recordedNot recordedVishay
- What it is
- Zener diode
- Maker
- Vishay
- Package
- Not recorded
- Pins
- Not recorded
- Details
- 68 V Zener diode
- Source
- From the manufacturer's datasheet
Is it dead? The meter test is below: Zener diode.
MSMP18ATVS diode, VishayTVS diodeNot recordedNot recordedVishay
- What it is
- TVS diode
- Maker
- Vishay
- Package
- Not recorded
- Pins
- Not recorded
- Details
- 150 W TVS diode, unidirectional
- Source
- From the manufacturer's datasheet
Is it dead? The meter test is below: TVS or ESD protection diode.
SMBG18ATVS diode, VishayTVS diodeNot recordedNot recordedVishay
- What it is
- TVS diode
- Maker
- Vishay
- Package
- Not recorded
- Pins
- Not recorded
- Details
- 600 W TVS diode, unidirectional
- Source
- From the manufacturer's datasheet
Is it dead? The meter test is below: TVS or ESD protection diode.
SMP18ATVS diode, VishayTVS diodeNot recordedNot recordedVishay
- What it is
- TVS diode
- Maker
- Vishay
- Package
- Not recorded
- Pins
- Not recorded
- Details
- 400 W TVS diode, unidirectional
- Source
- From the manufacturer's 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.
MOSFET
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
- 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.
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.
RF amplifier
Voltage, board powered, on the output pin that the bias resistor or choke feeds.
Working, it reads
The output pin sits at the device voltage the datasheet gives, a few volts, below the supply.
Dead, it reads
- Output pin at 0 V, or near 0 Ω to ground with the power off: shorted inside.
- Output pin at the full supply voltage: open inside, no current flowing.
- On the board:
- Measured on the board with power on; the bias network is part of the reading.
- 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 figures depend on the part and its bias resistor. The datasheet gives both.
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 BT
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 BT
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 1 more part.
Open this in the search to correct a character or try another package.