SMD code B1-
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.
149 parts are printed B1-
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.
BAS40SOT-23Schottky diode, 3 pins, Formosa MicrosemiSchottky diodeSOT-233 pinsFormosa Microsemi
- What it is
- Schottky diode
- Maker
- Formosa Microsemi
- Package
- SOT-23
- Pins
- 3
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
BAS40-Q1SOT-23Schottky diode, 3 pins, Formosa MicrosemiSchottky diodeSOT-233 pinsFormosa Microsemi
- What it is
- Schottky diode
- Maker
- Formosa Microsemi
- Package
- SOT-23
- Pins
- 3
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
BAS40LSOT-23Schottky diode, 3 pins, onsemiSchottky diodeSOT-233 pinsonsemi
- What it is
- Schottky diode
- Maker
- onsemi
- Package
- SOT-23
- Pins
- 3
- Details
- 0.2A, 40V, Surface Mount Small Signal Schottky Diodes
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
BAS70GPSOT-23Schottky diode, 3 pins, ChenmkoSchottky diodeSOT-233 pinsChenmko
- What it is
- Schottky diode
- Maker
- Chenmko
- Package
- SOT-23
- Pins
- 3
- Details
- SCHOTTKY DIODE, 70 V, 70 mA
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
BAT42WSSOD-323Schottky diode, 2 pins, Taiwan SemiconductorSchottky diodeSOD-3232 pinsTaiwan Semiconductor
- What it is
- Schottky diode
- Maker
- Taiwan Semiconductor
- Package
- SOD-323
- Pins
- 2
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
BZX84-C3V3SOT-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
- 3.3 V approx. ±5% voltage regulator (Zener) diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
BZX384B2V7SOD-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.
LBAS40LT1GSOT-23Schottky diode, 3 pins, LRCSchottky diodeSOT-233 pinsLRC
- What it is
- Schottky diode
- Maker
- LRC
- Package
- SOT-23
- Pins
- 3
- Details
- Schottky diode, VR 40 V, IF 0.12 A, VF Max 0.56 V
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
LBAS40WT1GSOT-323Schottky diode, 3 pins, LRCSchottky diodeSOT-3233 pinsLRC
- What it is
- Schottky diode
- Maker
- LRC
- Package
- SOT-323
- Pins
- 3
- Details
- Schottky diode, VR 40 V, IF 0.12 A, VF Max 0.56 V
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
LBZT52MB11T1GSOD-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 10.78 V, VZ Max 11.22 V, Vz@IZT mA 5
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
LUDZS11MBT1GSOD-323Zener diode, 2 pins, LRCZener diodeSOD-3232 pinsLRC
- What it is
- Zener diode
- Maker
- LRC
- Package
- SOD-323
- Pins
- 2
- Details
- Zener diode, VZ Min 10.78 V, VZ Max 11.22 V, Vz@IZT mA 5
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
PESDMC2FD5VBSOD-882ESD protection diode, 2 pins, PrisemiESD protection diodeSOD-8822 pinsPrisemi
- What it is
- ESD protection diode
- Maker
- Prisemi
- Package
- SOD-882
- Pins
- 2
- Details
- ESD protection diode, 5 V working
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: TVS or ESD protection diode.
3 more parts have no package on record
BCW61Transistor, InfineonTransistorNot recordedNot recordedInfineon
- What it is
- Transistor
- Maker
- Infineon
- Package
- Not recorded
- Pins
- Not recorded
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Bipolar transistor.
ET3895ETEKNot recordedNot recordedNot recordedETEK
- What it is
- Not recorded
- Maker
- ETEK
- Package
- Not recorded
- Pins
- Not recorded
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: This part.
HFCN-1500+RF filter, Mini-CircuitsRF filterNot recordedNot recordedMini-Circuits
- What it is
- RF filter
- Maker
- Mini-Circuits
- Package
- Not recorded
- Pins
- Not recorded
- Details
- LTCC filter, 1600-5500 MHz
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: This part.
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.
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.
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.
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.
This part
Diode range and ohms range, part lifted.
Working, it reads
Depends on what it is. The datasheet, or an identical part, says.
Dead, it reads
- Between two pins, the same reading both ways, near 0 V with a continuous beep: shorted.
- Open between every pair of pins: failed open, or a part that reads open when working.
- 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.
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.
Printed with a code easy to misread as B1-
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 24 more parts.
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