SMD code K120
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.
K120 on a chip resistor
120 Ω
120 Ω resistor
The K is both the decimal point and the multiplier: 120 Ω.
Check it with a meter
Lift one end and measure across it. A good one reads 120 Ω. Measuring it in circuit reads the parallel combination of everything around it, which is almost always lower, never higher: well above 120 Ω on the board is a fault. Open, or well above 120 Ω, means it has failed: burnt, cracked or corroded. That does not change what to fit: the marking still says 120 Ω. 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 (SOD-123F, SMA, SOT-23-5), K120 is a part code instead. Those parts are listed below.
5 parts are printed K120
Not sure which one you have?
Answer up to 4 quick questions and these 5 parts are ranked, with a meter test that settles it. It works on a dead part too.
DS120WSOD-123F2 pins, YFWSOD-123F2 pinsYFW
- What it is
- Schottky diode
- Maker
- YFW
- Package
- SOD-123F
- Pins
- 2
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
FM1200-MFLSOD-123F2 pins, Formosa MicrosemiSOD-123F2 pinsFormosa Microsemi
- What it is
- Schottky diode
- Maker
- Formosa Microsemi
- Package
- SOD-123F
- Pins
- 2
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
K120SDSOD-123F2 pins, YFWSOD-123F2 pinsYFW
- What it is
- Not recorded
- Maker
- YFW
- Package
- SOD-123F
- Pins
- 2
- Details
- Thyristor surge protector (TSS)
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: This part.
K1200S1URPSMA2 pins, LittelfuseSMA2 pinsLittelfuse
- What it is
- Not recorded
- Maker
- Littelfuse
- Package
- SMA
- Pins
- 2
- Details
- Silicon unilateral voltage triggered switch: Vbr=110..125V, Vrwm=100V, Ipp=120A(1ms)
- Source
- Published code list
Is it dead? The meter test is below: This part.
TS971ILTSOT-23-55 pins, STMicroelectronicsSOT-23-55 pinsSTMicroelectronics
- What it is
- Not recorded
- Maker
- STMicroelectronics
- Package
- SOT-23-5
- Pins
- 5
- 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.
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.
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.
Did you find your part?
Open this in the search to correct a character or try another package.