SMD code 3H
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.
4 parts are printed 3H
Not sure which one you have?
Answer up to 4 quick questions and these 4 parts are ranked, with a meter test that settles it. It works on a dead part too.
BC857SOT-23PNP transistor, 3 pins, NexperiaPNP transistorSOT-233 pinsNexperia
- What it is
- PNP transistor
- Maker
- Nexperia
- Package
- SOT-23
- Pins
- 3
- Pinout
- 1 base
- 2 emitter
- 3 collector
- Details
- 45 V, 100 mA PNP general-purpose transistor
- Source
- From the manufacturer's datasheet
Is it dead? The meter test is below: PNP transistor.
BC857WHSOT-323PNP transistor, 3 pins, Taiwan SemiconductorPNP transistorSOT-3233 pinsTaiwan Semiconductor
- What it is
- PNP transistor
- Maker
- Taiwan Semiconductor
- Package
- SOT-323
- Pins
- 3
- Source
- From the manufacturer's datasheet
Is it dead? The meter test is below: PNP transistor.
TL431BQPKSOT-89Voltage reference, 3 pins, Texas InstrumentsVoltage referenceSOT-893 pinsTexas Instruments
- What it is
- Voltage reference
- Maker
- Texas Instruments
- Package
- SOT-89
- Pins
- 3
- Details
- Precision Programmable Reference
- Source
- From the manufacturer's datasheet
Is it dead? The meter test is below: Integrated circuit.
1 more part has no package on record
VESD03D1-HD1ESD protection diode, VishayESD protection diodeNot recordedNot recordedVishay
- What it is
- ESD protection diode
- Maker
- Vishay
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Single-Line ESD-Protection Diode in DFN1006-2A
- Source
- From the manufacturer's datasheet
Is it dead? The meter test is below: TVS or ESD protection 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.
Integrated circuit
Voltage with the board powered; ohms from each pin to ground with it off.
Working, it reads
Supply pin at its voltage and the output doing what the datasheet says. Readings between pins depend on the part.
Dead, it reads
- A pin near 0 Ω to ground or to the supply pin where an identical part does not read that: failed short.
- Supply present, output stuck: failed, or its load has.
- On the board:
- A pin shorted to ground on the board can be anything on that net. Lift the pin to be sure.
- Compare:
- The surest reference is the same IC on a working board, measured pin by pin.
- Watch for:
- Its protection diodes can read like junctions between pins, even like a transistor. That proves nothing either way.
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.
Codes that begin with 3H
For a marking with its end worn or burnt off. Each code has a page of its own.
Open this in the search to correct a character or try another package.