SMD code BW-
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.
63 parts are printed BW-
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.
2SA2018SOT-416PNP transistor, 3 pins, ROHMPNP transistorSOT-4163 pinsROHM
- What it is
- PNP transistor
- Maker
- ROHM
- Package
- SOT-416
- Pins
- 3
- Details
- 12V, 0.5A, General Purpose PNP Bipolar Transistor
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: PNP transistor.
2SA2018E3SOT-416PNP transistor, 3 pins, ROHMPNP transistorSOT-4163 pinsROHM
- What it is
- PNP transistor
- Maker
- ROHM
- Package
- SOT-416
- Pins
- 3
- Details
- Low frequency transistor(-12V, -500mA)
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: PNP transistor.
2SA2018F-CSOT-523Transistor, 3 pins, SeCoSTransistorSOT-5233 pinsSeCoS
- What it is
- Transistor
- Maker
- SeCoS
- Package
- SOT-523
- Pins
- 3
- Details
- Bipolar transistor
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Bipolar transistor.
2SA2030SOT-723PNP transistor, 3 pins, ROHMPNP transistorSOT-7233 pinsROHM
- What it is
- PNP transistor
- Maker
- ROHM
- Package
- SOT-723
- Pins
- 3
- Details
- Low frequency transistor(-12V, -500mA)
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: PNP transistor.
2SA2119KSOT-23PNP transistor, 3 pins, ROHMPNP transistorSOT-233 pinsROHM
- What it is
- PNP transistor
- Maker
- ROHM
- Package
- SOT-23
- Pins
- 3
- Details
- 12V, 0.5A, Medium Power PNP Bipolar Transistor
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: PNP transistor.
BAS100ATB6SOT-563Schottky diode, 6 pins, PanjitSchottky diodeSOT-5636 pinsPanjit
- What it is
- Schottky diode
- Maker
- Panjit
- Package
- SOT-563
- Pins
- 6
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
BZT52H-C33SOD-123FZener diode, 2 pins, NexperiaZener diodeSOD-123F2 pinsNexperia
- What it is
- Zener diode
- Maker
- Nexperia
- Package
- SOD-123F
- Pins
- 2
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
CPDQ24VM-HFSOD-882ESD protection diode, 2 pins, ComchipESD protection diodeSOD-8822 pinsComchip
- What it is
- ESD protection diode
- Maker
- Comchip
- Package
- SOD-882
- Pins
- 2
- Details
- 24 V bidirectional ESD protection diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: TVS or ESD protection diode.
L2SD2114KWLT1GSOT-23NPN transistor, 3 pins, LRCNPN transistorSOT-233 pinsLRC
- What it is
- NPN transistor
- Maker
- LRC
- Package
- SOT-23
- Pins
- 3
- Details
- Bipolar transistor, NPN, IC 500 mA, VCEO 20 V
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: NPN transistor.
LBZT52MB15T1GSOD-123Zener diode, 2 pins, LRCZener diodeSOD-1232 pinsLRC
- What it is
- Zener diode
- Maker
- LRC
- Package
- SOD-123
- Pins
- 2
- Details
- Zener diode, VZ Min 14.7 V, VZ Max 15.3 V, Vz@IZT mA 5
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
LNZ8B15VT5GSOD-882Zener diode, 2 pins, LRCZener diodeSOD-8822 pinsLRC
- What it is
- Zener diode
- Maker
- LRC
- Package
- SOD-882
- Pins
- 2
- Details
- Zener diode, VZ Min 14.7 V, VZ Nom 15 V, VZ Max 15.3 V
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
4 more parts have no package on record
CDBQC0530L-HFSchottky diode, ComchipSchottky diodeNot recordedNot recordedComchip
- What it is
- Schottky diode
- Maker
- Comchip
- Package
- Not recorded
- Pins
- Not recorded
- Details
- 30 V, 0.5 A Schottky barrier diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
KRX208EDigital transistor (resistors built in), KECDigital transistor (resistors built in)Not recordedNot recordedKEC
- What it is
- Digital transistor (resistors built in)
- Maker
- KEC
- Package
- Not recorded
- Pins
- Not recorded
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Digital transistor.
KRX208UDigital transistor (resistors built in), KECDigital transistor (resistors built in)Not recordedNot recordedKEC
- What it is
- Digital transistor (resistors built in)
- Maker
- KEC
- Package
- Not recorded
- Pins
- Not recorded
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Digital transistor.
LFM0530-T1006Schottky diode, Formosa MicrosemiSchottky diodeNot recordedNot recordedFormosa Microsemi
- What it is
- Schottky diode
- Maker
- Formosa Microsemi
- Package
- Not recorded
- Pins
- Not recorded
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky 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.
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.
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.
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.
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.
Digital transistor
Ohms range, part lifted. The datasheet gives the built-in resistors: R1 in series with the base, R2 from base to emitter.
Working, it reads
Base to emitter reads about R1 plus R2 either way round, about 20 kΩ on a 10 k and 10 k part, give or take their wide tolerance. Collector to emitter reads open. A part with no R2 reads a junction behind R1 one way instead.
Dead, it reads
- Collector to emitter the same both ways, near 0 Ω with a continuous beep: shorted.
- From the base, open or far above R1 plus R2: R1 has failed. Static damage shows here most often.
- Base to emitter near 0 Ω: failed short.
- 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:
- The readings depend on the resistor values, so an identical part elsewhere on the board is the surest reference. Measure it the same way.
- Watch for:
- On the diode range a good part with 10 kΩ resistors reads open on every pair, so a good part looks dead there. Use the ohms range.
A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
NPN transistor
Diode range, part lifted or its base leg off the pad.
Working, it reads
Red 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.
Printed with a code easy to misread as BW-
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 BW-
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 1,338 more parts.
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