SMD code JS4
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.
12 parts are printed JS4
Not sure which one you have?
Answer up to 4 quick questions and these 12 parts are ranked, with a meter test that settles it. It works on a dead part too.
ABAS21S-HFSOT-233 pins, ComchipSOT-233 pinsComchip
- What it is
- Switching diode
- Maker
- Comchip
- Package
- SOT-23
- Pins
- 3
- Details
- 250 V, 200 mA switching diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
BAS21SSOT-233 pins, Galaxy MicroelectronicsSOT-233 pinsGalaxy Microelectronics
- What it is
- Switching diode
- Maker
- Galaxy Microelectronics
- Package
- SOT-23
- Pins
- 3
- Details
- 0.2A, 200V, Surface Mount Small Signal Switching Diodes
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
BAS21S-CSOT-233 pins, SeCoSSOT-233 pinsSeCoS
- What it is
- Switching diode
- Maker
- SeCoS
- Package
- SOT-23
- Pins
- 3
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
BAS21S-HFSOT-233 pins, ComchipSOT-233 pinsComchip
- What it is
- Switching diode
- Maker
- Comchip
- Package
- SOT-23
- Pins
- 3
- Details
- 250 V, 400 mA switching diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
BAS21S-P2-HFSOT-233 pins, ComchipSOT-233 pinsComchip
- What it is
- Switching diode
- Maker
- Comchip
- Package
- SOT-23
- Pins
- 3
- Details
- 250 V, 400 mA switching diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
BAS21SLT1GSOT-233 pins, HXYSOT-233 pinsHXY
- What it is
- Switching diode
- Maker
- HXY
- Package
- SOT-23
- Pins
- 3
- Details
- Switching diode, 250 V, 0.4 A
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
BAS21SN3SOT-233 pins, CYStekSOT-233 pinsCYStek
- What it is
- Switching diode
- Maker
- CYStek
- Package
- SOT-23
- Pins
- 3
- Details
- 250 V switching diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
BAV23SN3SOT-233 pins, CYStekSOT-233 pinsCYStek
- What it is
- Switching diode
- Maker
- CYStek
- Package
- SOT-23
- Pins
- 3
- Details
- 250 V switching diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
TBAS21SSOT-233 pins, Galaxy MicroelectronicsSOT-233 pinsGalaxy Microelectronics
- What it is
- Switching diode
- Maker
- Galaxy Microelectronics
- Package
- SOT-23
- Pins
- 3
- Details
- 0.2A, 250V, Surface Mount Small Signal Switching Diodes
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
2SA1815-4SOT-233 pins, Sanyo ElectricSOT-233 pinsSanyo Electric
- What it is
- Not recorded
- Maker
- Sanyo Electric
- Package
- SOT-23
- Pins
- 3
- Details
- pnp fm mix/amp Ft 750MHz hfe 90-180
- Source
- Published code list
Is it dead? The meter test is below: This part.
KAS21SSOT-233 pins, KEXIN GroupSOT-233 pinsKEXIN Group
- What it is
- Not recorded
- Maker
- KEXIN Group
- Package
- SOT-23
- Pins
- 3
- Details
- Diode: Dual, Sw, Fast, 200V, 250mA, Vf=1V(0.1A), 250mW, <50ns
- Source
- Published code list
Is it dead? The meter test is below: Silicon diode.
1 more part has no package on record
2SA1857-4Sanyo ElectricNot recordedNot recordedSanyo Electric
- What it is
- Not recorded
- Maker
- Sanyo Electric
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Si-pnp: RF, FM, IF-Amp, 15V, 50mA, 150mW, B=90..180, 750MHz
- 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.
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.
Printed with a code easy to misread as JS4
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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