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SMD code QI- in SOT-23

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.

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.

Nothing is printed exactly QI-

These parts are printed with a character that is easy to misread as what you typed. The odd one out is marked on each.

all SOT-23, 3 pins. What differs:

  • AZ23C5V6printed DISOT-23Zener diode, PanjitZener diodePanjit

    Printed DI on the part. Easy to misread as QI-. Check that character with a loupe before you order anything.

    What it is
    Zener diode
    Maker
    Panjit
    Package
    SOT-23
    Pins
    3
    Details
    5.6V, 300mW, Surface Mount Zener Diodes
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: Zener diode.

  • AZ23C5V6-AUprinted DISOT-23Zener diode, PanjitZener diodePanjit

    Printed DI on the part. Easy to misread as QI-. Check that character with a loupe before you order anything.

    What it is
    Zener diode
    Maker
    Panjit
    Package
    SOT-23
    Pins
    3
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: Zener diode.

  • AZ23C17printed DLSOT-23Zener diode, PanjitZener diodePanjit

    Printed DL on the part. Easy to misread as QI-. Check that character with a loupe before you order anything.

    What it is
    Zener diode
    Maker
    Panjit
    Package
    SOT-23
    Pins
    3
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: Zener diode.

  • BCW31printed D1SOT-23NPN transistor, Taitron ComponentsNPN transistorTaitron Components

    Printed D1 on the part. Easy to misread as QI-. Check that character with a loupe before you order anything.

    What it is
    NPN transistor
    Maker
    Taitron Components
    Package
    SOT-23
    Pins
    3
    Details
    Bipolar transistor, 40 V, 0.2 A
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: NPN transistor.

  • BL6202printed D1SOT-23P-channel MOSFET, Galaxy MicroelectronicsP-channel MOSFETGalaxy Microelectronics

    Printed D1 on the part. Easy to misread as QI-. Check that character with a loupe before you order anything.

    What it is
    P-channel MOSFET
    Maker
    Galaxy Microelectronics
    Package
    SOT-23
    Pins
    3
    Details
    60V, P Channel MOSFETs
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: P-channel MOSFET.

  • CHT2301GPprinted 01SOT-23P-channel MOSFET, ChenmkoP-channel MOSFETChenmko

    Printed 01 on the part. Easy to misread as QI-. Check that character with a loupe before you order anything.

    What it is
    P-channel MOSFET
    Maker
    Chenmko
    Package
    SOT-23
    Pins
    3
    Details
    P-Channel Enhancement Mode Field Effect Transistor, 20 V, 2.3 A
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: P-channel MOSFET.

  • KDR105Sprinted DLSOT-23Schottky diode, KECSchottky diodeKEC

    Printed DL on the part. Easy to misread as QI-. Check that character with a loupe before you order anything.

    What it is
    Schottky diode
    Maker
    KEC
    Package
    SOT-23
    Pins
    3
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: Schottky diode.

  • MMBZ5226Bprinted D1SOT-23Zener diode, DC ComponentsZener diodeDC Components

    Printed D1 on the part. Easy to misread as QI-. Check that character with a loupe before you order anything.

    What it is
    Zener diode
    Maker
    DC Components
    Package
    SOT-23
    Pins
    3
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: Zener diode.

  • PDTA143ETprinted 01SOT-23Digital transistor (PNP, resistors built in), NexperiaDigital transistor (PNP, resistors built in)Nexperia

    Printed 01 on the part. Easy to misread as QI-. Check that character with a loupe before you order anything.

    What it is
    Digital transistor (PNP, resistors built in)
    Maker
    Nexperia
    Package
    SOT-23
    Pins
    3
    Pinout
    • 1 base
    • 2 emitter
    • 3 collector
    Details
    50 V, 100 mA PNP resistor-equipped transistor; R1 = 4.7 kOhm, R2 = 4.7 kOhm
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: Digital transistor.

  • TBL6202printed D1SOT-23P-channel MOSFET, Galaxy MicroelectronicsP-channel MOSFETGalaxy Microelectronics

    Printed D1 on the part. Easy to misread as QI-. Check that character with a loupe before you order anything.

    What it is
    P-channel MOSFET
    Maker
    Galaxy Microelectronics
    Package
    SOT-23
    Pins
    3
    Details
    1.9A, 60V, 0.35W, P Channel, Power MOSFETs
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: P-channel MOSFET.

  • WPM5001-3printed 01SOT-23P-channel MOSFET, WillsemiP-channel MOSFETWillsemi

    Printed 01 on the part. Easy to misread as QI-. Check that character with a loupe before you order anything.

    What it is
    P-channel MOSFET
    Maker
    Willsemi
    Package
    SOT-23
    Pins
    3
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: P-channel MOSFET.

  • 2SA1343printed DLSOT-23Sanyo ElectricNot recordedSanyo Electric

    Printed DL on the part. Easy to misread as QI-. Check that character with a loupe before you order anything.

    What it is
    Not recorded
    Maker
    Sanyo Electric
    Package
    SOT-23
    Pins
    3
    Details
    Si-pnp-Digi: Sw, 50V, 100mA, 200MHz, R1/R2=47k/22k
    Source
    Published code list

    Is it dead? The meter test is below: This part.

  • 2SA1521printed OLSOT-23Sanyo ElectricNot recordedSanyo Electric

    Printed OL on the part. Easy to misread as QI-. Check that character with a loupe before you order anything.

    What it is
    Not recorded
    Maker
    Sanyo Electric
    Package
    SOT-23
    Pins
    3
    Details
    pre-biased sw pnp comp 2SC3915
    Source
    Published code list

    Is it dead? The meter test is below: Digital transistor.

  • 2SC2713-BLprinted DLSOT-23NPN transistor, ToshibaNPN transistorToshiba

    Printed DL on the part. Easy to misread as QI-. Check that character with a loupe before you order anything.

    What it is
    NPN transistor
    Maker
    Toshiba
    Package
    SOT-23
    Pins
    3
    Details
    Si-npn: GP, AF, 120V, 100mA, 150mW, B=350..700, 100MHz
    Source
    Published code list

    Is it dead? The meter test is below: NPN transistor.

  • 2SC2713BLprinted DLSOT-23ToshibaNot recordedToshiba

    Printed DL on the part. Easy to misread as QI-. Check that character with a loupe before you order anything.

    What it is
    Not recorded
    Maker
    Toshiba
    Package
    SOT-23
    Pins
    3
    Source
    Published code list

    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.

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.

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.

P-channel MOSFET

Diode range, part lifted. Test drain to source first, then short gate to source and test again.

Working, it reads

Red probe on the drain, black on the source: about 0.4 to 0.9 V, the body diode. Open the other way. The gate reads open to both other pins, both ways.

Dead, it reads

  • Drain to source the same both ways, near 0 V with a continuous beep, and still so after shorting gate to source: shorted. The classic failure.
  • The gate reads low to source or drain: gate shorted. Often all three pins end up shorted together.
  • No body diode at all: failed open.
On the board
the gate usually has a resistor to the source, so gate to source reads that resistor, which is not a fault. Lift a leg to be sure.
Compare:
If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.
Watch for:
The diode range can charge the gate enough to turn the part on, and then drain to source reads near 0 both ways on a good part. Short gate to source and test again before you condemn it.

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.

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.

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.

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.

Codes that begin with QI-

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 4,116 more parts.

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