SMD code A3-
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.
220 parts are printed A3-
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.
FM4003-NSOD-323Rectifier, 2 pins, Formosa MicrosemiRectifierSOD-3232 pinsFormosa Microsemi
- What it is
- Rectifier
- Maker
- Formosa Microsemi
- Package
- SOD-323
- Pins
- 2
- Details
- Rectifier diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
FM4003-N-Q1SOD-323Rectifier, 2 pins, Formosa MicrosemiRectifierSOD-3232 pinsFormosa Microsemi
- What it is
- Rectifier
- Maker
- Formosa Microsemi
- Package
- SOD-323
- Pins
- 2
- Details
- Rectifier diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
FM4003-Q1SMARectifier, 2 pins, Formosa MicrosemiRectifierSMA2 pinsFormosa Microsemi
- What it is
- Rectifier
- Maker
- Formosa Microsemi
- Package
- SMA
- Pins
- 2
- Details
- Rectifier diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
FMA3ASOT-23-5Digital transistor (resistors built in), 5 pins, ROHMDigital transistor (resistors built in)SOT-23-55 pinsROHM
- What it is
- Digital transistor (resistors built in)
- Maker
- ROHM
- Package
- SOT-23-5
- Pins
- 5
- Details
- Emitter common(dual digital transistor)
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Digital transistor.
GSA3SOD-123FRectifier, 2 pins, Good-ArkRectifierSOD-123F2 pinsGood-Ark
- What it is
- Rectifier
- Maker
- Good-Ark
- Package
- SOD-123F
- Pins
- 2
- Details
- Rectifier, 200 V, 1 A
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
HDAP202KT146SOT-23Switching diode, 3 pins, HXYSwitching diodeSOT-233 pinsHXY
- What it is
- Switching diode
- Maker
- HXY
- Package
- SOT-23
- Pins
- 3
- Details
- Switching diode, 85 V, 0.1 A
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
9 more parts have no package on record
FM4003-MHRectifier, Formosa MicrosemiRectifierNot recordedNot recordedFormosa Microsemi
- What it is
- Rectifier
- Maker
- Formosa Microsemi
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Rectifier diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
FM4003-MH-Q1Rectifier, Formosa MicrosemiRectifierNot recordedNot recordedFormosa Microsemi
- What it is
- Rectifier
- Maker
- Formosa Microsemi
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Rectifier diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
FM4003-MSRectifier, Formosa MicrosemiRectifierNot recordedNot recordedFormosa Microsemi
- What it is
- Rectifier
- Maker
- Formosa Microsemi
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Rectifier diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
FM4003-MS-Q1Rectifier, Formosa MicrosemiRectifierNot recordedNot recordedFormosa Microsemi
- What it is
- Rectifier
- Maker
- Formosa Microsemi
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Rectifier diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
FM4003-MSTRectifier, Formosa MicrosemiRectifierNot recordedNot recordedFormosa Microsemi
- What it is
- Rectifier
- Maker
- Formosa Microsemi
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Rectifier diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
FM4003-MST-Q1Rectifier, Formosa MicrosemiRectifierNot recordedNot recordedFormosa Microsemi
- What it is
- Rectifier
- Maker
- Formosa Microsemi
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Rectifier diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
FM4003-SFRectifier, Formosa MicrosemiRectifierNot recordedNot recordedFormosa Microsemi
- What it is
- Rectifier
- Maker
- Formosa Microsemi
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Rectifier diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
FM4003-SF-Q1Rectifier, Formosa MicrosemiRectifierNot recordedNot recordedFormosa Microsemi
- What it is
- Rectifier
- Maker
- Formosa Microsemi
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Rectifier diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
KDS120Switching diode, KECSwitching diodeNot recordedNot recordedKEC
- What it is
- Switching diode
- Maker
- KEC
- Package
- Not recorded
- Pins
- Not recorded
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon 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.
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.
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.
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