SMD code 81H
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.
81H on a chip resistor
6.81 kΩ
6.81 kΩ resistor, 1%
EIA-96 precision code: 81 selects 6.81 from the E96 series and H multiplies by 1000. These are 1% parts.
Check it with a meter
Lift one end and measure across it. A good one reads 6.81 kΩ within 1%. Measuring it in circuit reads the parallel combination of everything around it, which is almost always lower, never higher: well above 6.81 kΩ on the board is a fault. Open, or well above 6.81 kΩ, means it has failed: burnt, cracked or corroded. That does not change what to fit: the marking still says 6.81 kΩ. A burnt resistor usually means the part it feeds drew too much, so find that before fitting a new one.
On a transistor or diode body (SOT-23, SOT-23-5, DFN), 81H is a part code instead. Those parts are listed below.
24 parts are printed 81H
Not sure which one you have?
Answer up to 4 quick questions and these 24 parts are ranked, with a meter test that settles it. It works on a dead part too.
LMBZ5257BLT1GSOT-23Zener diode, 3 pins, LRCZener diodeSOT-233 pinsLRC
- What it is
- Zener diode
- Maker
- LRC
- Package
- SOT-23
- Pins
- 3
- Details
- Zener diode, VZ Min 31.35 V, VZ Nom 33 V, VZ Max 34.65 V
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
MMBZ5257BSOT-23Zener diode, 3 pins, Taitron ComponentsZener diodeSOT-233 pinsTaitron Components
- What it is
- Zener diode
- Maker
- Taitron Components
- Package
- SOT-23
- Pins
- 3
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
MMBZ5257BLSOT-23Zener diode, 3 pins, onsemiZener diodeSOT-233 pinsonsemi
- What it is
- Zener diode
- Maker
- onsemi
- Package
- SOT-23
- Pins
- 3
- Details
- Zener Voltage Regulators MMBZ52xxBLT1G Series, SZMMBZ52xxBLT1G Series
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
S-LMBZ5257BLT1GSOT-23Zener diode, 3 pins, LRCZener diodeSOT-233 pinsLRC
- What it is
- Zener diode
- Maker
- LRC
- Package
- SOT-23
- Pins
- 3
- Details
- Zener diode, VZ Min 31.35 V, VZ Nom 33 V, VZ Max 34.65 V
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
ZD5257AN3SOT-23Zener diode, 3 pins, CYStekZener diodeSOT-233 pinsCYStek
- What it is
- Zener diode
- Maker
- CYStek
- Package
- SOT-23
- Pins
- 3
- Details
- 33 V zener diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
ZD5257BN3SOT-23Zener diode, 3 pins, CYStekZener diodeSOT-233 pinsCYStek
- What it is
- Zener diode
- Maker
- CYStek
- Package
- SOT-23
- Pins
- 3
- Details
- 33 V zener diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
CMBZ5257BSOT-233 pins, MEI SemiNot recordedSOT-233 pinsMEI Semi
- What it is
- Not recorded
- Maker
- MEI Semi
- Package
- SOT-23
- Pins
- 3
- Details
- Z-diode: 33V±5%, Izt=3.8mA, Zzt=58Ω, 300mW
- Source
- Published code list
Is it dead? The meter test is below: Silicon diode.
CMPZ5257BSOT-23Zener diode, 3 pinsZener diodeSOT-233 pinsNot recorded
- What it is
- Zener diode
- Maker
- Not recorded
- Package
- SOT-23
- Pins
- 3
- Details
- Z-diode: 33V±2.5%, Izt=3.8mA, Zzt=58Ω, 350mW
- Source
- Published code list
Is it dead? The meter test is below: Zener diode.
FDZS33LTSOT-23Zener diode, 3 pins, First SilionZener diodeSOT-233 pinsFirst Silion
- What it is
- Zener diode
- Maker
- First Silion
- Package
- SOT-23
- Pins
- 3
- Details
- Zener diode: 31.35..34.65V, Izt=3.8mA, Zzt=58, 225mW
- Source
- Published code list
Is it dead? The meter test is below: Zener diode.
FMMD5257SOT-233 pins, Diodes IncorporatedNot recordedSOT-233 pinsDiodes Incorporated
- What it is
- Not recorded
- Maker
- Diodes Incorporated
- Package
- SOT-23
- Pins
- 3
- Source
- Published code list
Is it dead? The meter test is below: This part.
FMMZ5257SOT-233 pins, Diodes IncorporatedNot recordedSOT-233 pinsDiodes Incorporated
- What it is
- Not recorded
- Maker
- Diodes Incorporated
- Package
- SOT-23
- Pins
- 3
- Source
- Published code list
Is it dead? The meter test is below: This part.
HMBZ5257BSOT-233 pins, Hi-Sincerity MicroelectronicsNot recordedSOT-233 pinsHi-Sincerity Microelectronics
- What it is
- Not recorded
- Maker
- Hi-Sincerity Microelectronics
- Package
- SOT-23
- Pins
- 3
- Details
- Z-diode: 33V±5%, Izt=3.8mA, Zzt=58Ω, 225mW
- Source
- Published code list
Is it dead? The meter test is below: Silicon diode.
LMBZ5257BLSOT-23Zener diode, 3 pins, LRCZener diodeSOT-233 pinsLRC
- What it is
- Zener diode
- Maker
- LRC
- Package
- SOT-23
- Pins
- 3
- Details
- Zener diode: 31.35..34.65V, Izt=3.8mA, 225mW
- Source
- Published code list
Is it dead? The meter test is below: Zener diode.
MMBZ5257SOT-23Zener diode, 3 pins, VishayZener diodeSOT-233 pinsVishay
- What it is
- Zener diode
- Maker
- Vishay
- Package
- SOT-23
- Pins
- 3
- Source
- Published code list
Is it dead? The meter test is below: Zener diode.
1 more part has no package on record
IXD9208A1H3DRDC-DC converter, ZilogDC-DC converterNot recordedNot recordedZilog
- What it is
- DC-DC converter
- Maker
- Zilog
- Package
- Not recorded
- Pins
- Not recorded
- Details
- DC/DC voltage converter IC: PWM st-dwn, 3MHz, 1.65V±2%, 400mA, +CE
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
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.
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.
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.
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.
Printed with a code easy to misread as 81H
One character differs, and it is one that is easy to confuse under a lamp. Each code has a page of its own.
Did you find your part?
Open this in the search to correct a character or try another package.