SMD code K74
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.
K74 on a chip resistor
740 Ω
740 Ω resistor
The K is both the decimal point and the multiplier: 740 Ω.
Check it with a meter
Lift one end and measure across it. A good one reads 740 Ω. Measuring it in circuit reads the parallel combination of everything around it, which is almost always lower, never higher: well above 740 Ω on the board is a fault. Open, or well above 740 Ω, means it has failed: burnt, cracked or corroded. That does not change what to fit: the marking still says 740 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 (SOT-23, SOT-323, SOT-23-5), K74 is a part code instead. Those parts are listed below.
7 parts are printed K74
Not sure which one you have?
Answer up to 4 quick questions and these 7 parts are ranked, with a meter test that settles it. It works on a dead part too.
BAS70-04-CSOT-23Schottky diode, 3 pins, SeCoSSchottky diodeSOT-233 pinsSeCoS
- What it is
- Schottky diode
- Maker
- SeCoS
- Package
- SOT-23
- Pins
- 3
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
BAS70DW-04SOT-363Schottky diode, 6 pins, Galaxy MicroelectronicsSchottky diodeSOT-3636 pinsGalaxy Microelectronics
- What it is
- Schottky diode
- Maker
- Galaxy Microelectronics
- Package
- SOT-363
- Pins
- 6
- Details
- 0.07A, 70V, Surface Mount Small Signal Schottky Diodes
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
BAS70W-04SOT-323Schottky diode, 3 pins, Galaxy MicroelectronicsSchottky diodeSOT-3233 pinsGalaxy Microelectronics
- What it is
- Schottky diode
- Maker
- Galaxy Microelectronics
- Package
- SOT-323
- Pins
- 3
- Details
- 0.07A, 70V, Surface Mount Small Signal Schottky Diodes
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
TBAS70W-04SOT-323Schottky diode, 3 pins, Galaxy MicroelectronicsSchottky diodeSOT-3233 pinsGalaxy Microelectronics
- What it is
- Schottky diode
- Maker
- Galaxy Microelectronics
- Package
- SOT-323
- Pins
- 3
- Details
- 0.07A, 70V, Surface Mount Small Signal Schottky Diodes
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
BAS70-04SOT-23Switching diode, 3 pins, Diodes IncorporatedSwitching diodeSOT-233 pinsDiodes Incorporated
- What it is
- Switching diode
- Maker
- Diodes Incorporated
- Package
- SOT-23
- Pins
- 3
- Source
- Published code list
Is it dead? The meter test is below: Silicon diode.
BAS70-04WSOT-323Schottky diode, 3 pins, SecosSchottky diodeSOT-3233 pinsSecos
- What it is
- Schottky diode
- Maker
- Secos
- Package
- SOT-323
- Pins
- 3
- Details
- SMD Small Signal Schottky Diodes
- Source
- Published code list
Is it dead? The meter test is below: Schottky diode.
1 more part has no package on record
BAS70W-04-7-F3 pins, Diodes IncorporatedNot recordedNot recorded3 pinsDiodes Incorporated
- What it is
- Not recorded
- Maker
- Diodes Incorporated
- Package
- Not recorded
- Pins
- 3
- Details
- SCHOTTKY DUAL
- Source
- Published code list
Is it dead? The meter test is below: Schottky 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.
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.
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.
Printed with a code easy to misread as K74
One character differs, and it is one that is easy to confuse under a lamp. Each code has a page of its own.
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