SMD code JB-
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.
60 parts are printed JB-
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.
BAR74SOT-23PIN diode, 3 pins, InfineonPIN diodeSOT-233 pinsInfineon
- What it is
- PIN diode
- Maker
- Infineon
- Package
- SOT-23
- Pins
- 3
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: PIN diode or varicap.
BAV99SOT-23Switching diode, 3 pins, PanjitSwitching diodeSOT-233 pinsPanjit
- What it is
- Switching diode
- Maker
- Panjit
- Package
- SOT-23
- Pins
- 3
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
BAV99-AUSOT-23Switching diode, 3 pins, PanjitSwitching diodeSOT-233 pinsPanjit
- What it is
- Switching diode
- Maker
- Panjit
- Package
- SOT-23
- Pins
- 3
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
BAV99SSOT-363Switching diode, 6 pins, PanjitSwitching diodeSOT-3636 pinsPanjit
- What it is
- Switching diode
- Maker
- Panjit
- Package
- SOT-363
- Pins
- 6
- Details
- 0.2A, 75V, Surface Mount Small Signal Switching Diodes
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
BAV99S-AUSOT-363Switching diode, 6 pins, PanjitSwitching diodeSOT-3636 pinsPanjit
- What it is
- Switching diode
- Maker
- Panjit
- Package
- SOT-363
- Pins
- 6
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
BAV99WSOT-323Switching diode, 3 pins, PanjitSwitching diodeSOT-3233 pinsPanjit
- What it is
- Switching diode
- Maker
- Panjit
- Package
- SOT-323
- Pins
- 3
- Details
- 0.215A, 100V, Surface Mount Small Signal Switching Diodes
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
CH661H-20GPSOT-363Schottky diode, 6 pins, ChenmkoSchottky diodeSOT-3636 pinsChenmko
- What it is
- Schottky diode
- Maker
- Chenmko
- Package
- SOT-363
- Pins
- 6
- Details
- SCHOTTKY BARRIER DIODE, 15 V, 0.1 A
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
CH761UGPSOT-363Schottky diode, 6 pins, ChenmkoSchottky diodeSOT-3636 pinsChenmko
- What it is
- Schottky diode
- Maker
- Chenmko
- Package
- SOT-363
- Pins
- 6
- Details
- SCHOTTKY BARRIER DIODE, 12 V, 0.1 A
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
KDZV4.3BSOD-123FZener diode, 2 pins, ROHMZener diodeSOD-123F2 pinsROHM
- What it is
- Zener diode
- Maker
- ROHM
- Package
- SOD-123F
- Pins
- 2
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
KDZVTF4.3BSOD-123FZener diode, 2 pins, ROHMZener diodeSOD-123F2 pinsROHM
- What it is
- Zener diode
- Maker
- ROHM
- Package
- SOD-123F
- Pins
- 2
- Details
- Zener Diode (AEC-Q101 qualified)
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
MMBTA56SOT-23PNP transistor, 3 pins, DiotecPNP transistorSOT-233 pinsDiotec
- What it is
- PNP transistor
- Maker
- Diotec
- Package
- SOT-23
- Pins
- 3
- Details
- PNP bipolar transistor
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: PNP transistor.
4 more parts have no package on record
KRA722EDigital transistor (PNP, resistors built in), KECDigital transistor (PNP, resistors built in)Not recordedNot recordedKEC
- What it is
- Digital transistor (PNP, resistors built in)
- Maker
- KEC
- Package
- Not recorded
- Pins
- Not recorded
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Digital transistor.
KRA722UDigital transistor (PNP, resistors built in), KECDigital transistor (PNP, resistors built in)Not recordedNot recordedKEC
- What it is
- Digital transistor (PNP, resistors built in)
- Maker
- KEC
- Package
- Not recorded
- Pins
- Not recorded
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Digital transistor.
MM5Z22VBZener diode, Formosa MicrosemiZener diodeNot recordedNot recordedFormosa Microsemi
- What it is
- Zener diode
- Maker
- Formosa Microsemi
- Package
- Not recorded
- Pins
- Not recorded
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
MM5Z22VB-Q1Zener diode, Formosa MicrosemiZener diodeNot recordedNot recordedFormosa Microsemi
- What it is
- Zener diode
- Maker
- Formosa Microsemi
- Package
- Not recorded
- Pins
- Not recorded
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener 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.
PIN diode or varicap
Diode range, part lifted or one leg off the pad. Red probe on the anode.
Working, it reads
About 0.6 to 0.9 V anode to cathode, 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.
- 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 varicap that has drifted in capacitance reads normal on a meter. Only a capacitance meter or the tuning itself shows it.
A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
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.
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.
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.
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.
Printed with a code easy to misread as JB-
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 4 more parts.
Did you find your part?
Open this in the search to correct a character or try another package.