SMD code 3Ab
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.
The last letter, b, is lower case, which on NXP and Philips parts is a date or factory code, so it was set aside and 3A was searched.
145 parts are printed 3Ab
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.
1N4448WSSOD-323Switching diode, 2 pins, VishaySwitching diodeSOD-3232 pinsVishay
- What it is
- Switching diode
- Maker
- Vishay
- Package
- SOD-323
- Pins
- 2
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
ABC856A-HFSOT-23PNP transistor, 3 pins, ComchipPNP transistorSOT-233 pinsComchip
- What it is
- PNP transistor
- Maker
- Comchip
- Package
- SOT-23
- Pins
- 3
- Details
- -65 V, -0.1 A PNP transistor
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: PNP transistor.
ABC856AW-HFSOT-323PNP transistor, 3 pins, ComchipPNP transistorSOT-3233 pinsComchip
- What it is
- PNP transistor
- Maker
- Comchip
- Package
- SOT-323
- Pins
- 3
- Details
- -65 V, -0.1 A PNP transistor
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: PNP transistor.
AMMSZ5263AS-HFSOD-323Zener diode, 2 pins, ComchipZener diodeSOD-3232 pinsComchip
- What it is
- Zener diode
- Maker
- Comchip
- Package
- SOD-323
- Pins
- 2
- Details
- 56 V 200 mW zener diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
BC856SOT-23PNP transistor, 3 pins, InfineonPNP transistorSOT-233 pinsInfineon
- What it is
- PNP transistor
- Maker
- Infineon
- Package
- SOT-23
- Pins
- 3
- Details
- PNP bipolar transistor
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: PNP transistor.
BC856ASOT-23PNP transistor, 3 pins, Formosa MicrosemiPNP transistorSOT-233 pinsFormosa Microsemi
- What it is
- PNP transistor
- Maker
- Formosa Microsemi
- Package
- SOT-23
- Pins
- 3
- Pinout
- 1 base
- 2 emitter
- 3 collector
- Details
- -80 V PNP small-signal transistor, gain group A
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: PNP transistor.
BC856A-CSOT-23Transistor, 3 pins, SeCoSTransistorSOT-233 pinsSeCoS
- What it is
- Transistor
- Maker
- SeCoS
- Package
- SOT-23
- Pins
- 3
- Details
- Bipolar transistor
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Bipolar transistor.
BC856A-HFSOT-23PNP transistor, 3 pins, ComchipPNP transistorSOT-233 pinsComchip
- What it is
- PNP transistor
- Maker
- Comchip
- Package
- SOT-23
- Pins
- 3
- Details
- -65 V, -0.1 A PNP transistor
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: PNP transistor.
BC856ADWSOT-363Dual PNP transistor, 6 pins, Formosa MicrosemiDual PNP transistorSOT-3636 pinsFormosa Microsemi
- What it is
- Dual PNP transistor
- Maker
- Formosa Microsemi
- Package
- SOT-363
- Pins
- 6
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: PNP transistor pair.
BC856ADW-Q1SOT-363Dual PNP transistor, 6 pins, Formosa MicrosemiDual PNP transistorSOT-3636 pinsFormosa Microsemi
- What it is
- Dual PNP transistor
- Maker
- Formosa Microsemi
- Package
- SOT-363
- Pins
- 6
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: PNP transistor pair.
BC856ALSOT-23PNP transistor, 3 pins, onsemiPNP transistorSOT-233 pinsonsemi
- What it is
- PNP transistor
- Maker
- onsemi
- Package
- SOT-23
- Pins
- 3
- Details
- 65V, 0.1A, General Purpose PNP Bipolar Transistor
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: PNP transistor.
BC856AWSOT-323Transistor, 3 pins, DiotecTransistorSOT-3233 pinsDiotec
- What it is
- Transistor
- Maker
- Diotec
- Package
- SOT-323
- Pins
- 3
- Details
- SMD General Purpose PNP Transistors
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Bipolar transistor.
BC856AW-HFSOT-323PNP transistor, 3 pins, ComchipPNP transistorSOT-3233 pinsComchip
- What it is
- PNP transistor
- Maker
- Comchip
- Package
- SOT-323
- Pins
- 3
- Details
- -65 V, -0.1 A PNP transistor
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: PNP transistor.
BC856AW-Q1SOT-323PNP transistor, 3 pins, Formosa MicrosemiPNP transistorSOT-3233 pinsFormosa Microsemi
- What it is
- PNP transistor
- Maker
- Formosa Microsemi
- Package
- SOT-323
- Pins
- 3
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: PNP transistor.
BCM847BVSOT-563NPN transistor, 6 pins, NexperiaNPN transistorSOT-5636 pinsNexperia
- What it is
- NPN transistor
- Maker
- Nexperia
- Package
- SOT-563
- Pins
- 6
- Details
- NPN/NPN matched double transistor
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: NPN transistor.
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.
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.
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.
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.
PNP transistor pair
Diode range, part lifted. Test each transistor on its own pins, as the datasheet's pinout gives them.
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.
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 3Ab
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 3Ab
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 1,497 more parts.
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