Chip Resistor Jumpers and 0 Ω Parts: What the 000 Code Actually Rates

A 0 Ω resistor jumper is rated in amps, not in watts. The 000 code in a Walsin
Technology (Walsin) chip resistor part number marks a jumper with a resistance of 50 mΩ or
less. Walsin’s parametric export publishes a rated power on all 126 jumper rows and a rated
current on none. The current figure is in the datasheet.

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Venatech Limited, an authorised Walsin distributor in Hong Kong, holds all 137 of Walsin’s
chip resistor export files — 234,815 rows. This post is written from that extract and from
the two Walsin chip resistor datasheets we hold on file. Every part number below is a real
part in that data.

What does the 000 code in a Walsin chip resistor part number mean?

000 in the resistance field marks a jumper. It is not the E24 three-digit code for zero
ohms, because zero ohms has no E24 code. Walsin’s ordering key defines 000_ — three zeros
followed by a blank — as the P-tolerance jumper. The trailing blank is a real character in
the part number, not a typographic accident.

So MR04X000 PTL decomposes as MR04 (0402 automotive thick film), X (jumper), 000 plus a
space (the jumper resistance code), then P, T and L for tolerance, packaging and termination.
The X in position five and the 000 both say jumper. Neither is redundant: the export
writes Jumper in the Tolerance column and 0Ω in the Resistance column, and the part
number encodes both.

What is the actual resistance of a 0 Ω jumper?

Not zero. Walsin specifies the jumper as 50 mΩ maximum for P tolerance and 30 mΩ maximum for
F tolerance. The general purpose datasheet states it a third way — “the resistance of Jumper
is defined <0.05” — which is the same 50 mΩ ceiling written as ohms. A 0 Ω part in a series
circuit adds up to 50 mΩ, and the export’s 0Ω entry does not tell you that.

At 3 A through 50 mΩ, the drop is 150 mV and the dissipation is 450 mW. That matters on a
sense return, on a low-voltage rail, and anywhere a jumper sits inside a feedback path.

Is a 0 Ω resistor rated in watts or in amps?

In amps. Rated power is meaningless as a selection limit for a jumper, because the
dissipation depends on a resistance specified only as a ceiling. Walsin still publishes a
rated power on every jumper row, and it is the dissipation figure inherited from the
resistive parts in the same series and case size — not a limit derived from the jumper.

We checked that claim against the datasheet across all five MR sizes. The export’s rated
power matches the datasheet’s maximum dissipation exactly, which confirms it is the series
figure, copied down:

Part number	Case size	Export rated power	Datasheet max. dissipation @ 70 °C	Match / mismatch
MR10X000 PTL	1210 (3225)	1/2 W	1/2 W	Match
MR12X000 PTL	1206 (3216)	1/4 W	1/4 W	Match
MR08X000 PTL	0805 (2012)	1/4 W	1/4 W	Match
MR06X000 PTL	0603 (1608)	1/8 W	1/8 W	Match
MR04X000 PTL	0402 (1005)	1/10 W	1/10 W	Match

Source: Walsin_MR_Automotive_Thick_Film_Chip_Resistor.pdf, page 3.

The figures agree. That is the problem. A designer filtering on rated power gets a number
that is real for the series and tells them nothing about how much current the jumper will
take.

What current can a Walsin chip resistor jumper carry?

The MR datasheet tabulates rated and peak current per case size, separately for the two
jumper tolerances. This table is in the PDF and in none of the 137 export files:

Case size	Part number in our extract	P tol. rated current	P tol. peak	F tol. rated current	F tol. peak	In the parametric export?
1210 (3225)	MR10X000 PTL	3 A	7.5 A	4 A	10 A	P only — mismatch
1206 (3216)	MR12X000 PTL	2 A	5 A	2.9 A	5.8 A	P only — mismatch
0805 (2012)	MR08X000 PTL	1.5 A	3.5 A	2 A	4 A	P only — mismatch
0603 (1608)	MR06X000 PTL	1 A	3 A	1.8 A	3.6 A	P only — mismatch
0402 (1005)	MR04X000 PTL	1 A	2 A	1 A	2 A	P only — mismatch

Source: Walsin_MR_Automotive_Thick_Film_Chip_Resistor.pdf, page 3. The same datasheet states
that TCR is not applicable to jumper product.

Two things follow. The F-tolerance jumper carries up to a third more continuous current than
the P-tolerance part in the same footprint — 4 A against 3 A at 1210, 1.8 A against 1 A at
0603. And at 0402 the two tolerances are rated identically, so the tighter part buys nothing
in current at the smallest size.

Why does one case size show four different power ratings?

Because the rating travels with the series, not the footprint. The 0402 case alone holds 21
jumper rows in our extract, spread across four rated power figures: 1/16 W, 1/10 W, 1/8 W and
1/5 W. “An 0402 jumper” is not a specification.

Part number	Series	Case size	Export rated power	Match / mismatch vs. WF04A000 PTL
WF04A000 PTL	Thick Film High Power Chip Resistor	0402 (1005)	1/5 W	Reference part
WF04P000 PTL	Thick Film High Power Chip Resistor	0402 (1005)	1/8 W	Same series and size; rated power differs
MR04X000 PTL	Thick Film General Purpose (Automotive)	0402 (1005)	1/10 W	Size matches; series and rated power differ
WR04X000 PTL	Thick Film General Purpose	0402 (1005)	1/16 W	Size matches; series and rated power differ
WA04X000 PTL	Thick Film Chip Resistor Array 0402×4	0402 (1005)	1/16 W	Four elements, not one; not a substitution

WF04A000 PTL and WF04P000 PTL are the sharpest case. Same series group, same case size,
one character apart in the part number, and a rated power that differs by a factor of 1.6.
The character in position five carries the rating.

The same pattern appears at 2010. WR20X000 PTL is rated 3/4 W; WR20X000 PTLJ and
WR20X000 PTR — the automotive and the LF 100 ppm variants of the same base number — are
rated 1/2 W. A suffix you might read as packaging changes the published rating.

How many jumpers does Walsin list, and where are they hidden?

Our extract holds 126 jumper rows and 125 distinct jumper part numbers. WF04A000 PTL
appears twice, once in the high-power jumper export and once in the 1/5 W high-power export.

Only 108 of those rows sit in the seven exports whose names say jumper, and four of those
seven return nothing at all:

Walsin jumper export	Rows returned	Match / mismatch vs. its own filename
Thick Film General Purpose, Jumper	74	Match
Thick Film High Power Chip Resistor, Jumper	33	Match
High Power, jumper, 1/5 W	1	Match
High Precision Thick Film, Jumper	0	Mismatch — empty
Thick Film Anti-Surge, Jumper	0	Mismatch — empty
Thick Film High Power, Jumper, 1.5 W	0	Mismatch — empty
Thick Film High Voltage, Jumper	0	Mismatch — empty

The remaining 18 jumpers are filed under resistor arrays, the convex-type resistor network
and, in one case, a chip attenuator. WT04X000 PTL is a 1206 jumper inside the network
export. WA06W000 PTLN is an 0602×8 array jumper. Anyone who downloads the jumper filter and
treats it as the jumper range is working from 108 parts and missing 18.

One of the 18 is not a resistor. WA04P000XPTL is a chip attenuator: its Tolerance column
reads Jumper and its Resistance column reads 0dB. It is a 0 dB attenuator, correctly
described and wrongly grouped. Filter the catalogue for jumpers and it comes back with them.

Exactly one jumper in the 126 publishes a TCR. WF10P000 PTL, a 1210 high-power part, carries
≦±100 where the other 125 carry a dash — and the MR datasheet says TCR does not apply to
jumper product at all.

What is the 0000 code, and why can you not find it?

0000 — four zeros, no blank — is Walsin’s code for the F-tolerance jumper at 30 mΩ maximum.
It appears in the ordering key on page 4 of the MR datasheet. It appears in zero of the
234,815 rows across all 137 chip resistor export files.

Every jumper Walsin publishes parametric data for is the P version at 50 mΩ. The tighter part
with the higher current rating — the one worth 4 A at 1210 instead of 3 A — is documented and
not listed. If your design needs it, you have to ask for it by name, because no amount of
filtering will surface it.

Four MR jumper sizes have the opposite problem. MR02X000 PAL (0201), MR18X000 PTL (1218),
MR20X000 PTL (2010) and MR25X000 PTL (2512) are real parts in the export, and the MR
datasheet we hold covers only MR04, MR06, MR08, MR10 and MR12. No rated current is published
for those four anywhere we can see.

Why will a jumper part number not paste into your BOM?

Because 125 of the 126 jumper part numbers contain an embedded space. The 000_ code ends in
a blank, and the blank is in the string: MR04X000 PTL, WF25A000 PZL, SA06Y000 PTL. Paste
any of them into a BOM field or a search box unmodified and it will not resolve. The single
exception is WA04P000XPTL, the attenuator — the one row that is not a jumper is also the
one row with no space.

This is not theoretical. Four jumpers appear in our 23 September 2026 ready-stock snapshot,
written without the space:

Walsin export writes	Our stock file writes	Match / mismatch
WR04X000 PTL	WR04X000PTL	Same part; space only
WR06X000 PTL	WR06X000PTL	Same part; space only
WR08X000 PTL	WR08X000PTL	Same part; space only
WR12X000 PTL	WR12X000PTL	Same part; space only

A join on part number across those two files returns nothing. Strip the space first. Stock is
a snapshot and moves; ask us for the current position rather than relying on a date.

The wider pattern is covered in
Why Walsin part numbers do not paste into your BOM.
For how rated power behaves across case sizes on the resistive parts, see
Chip resistor power rating by case size.
The full range is on the Walsin chip resistor range page.

The short version

Select a jumper on current, from the datasheet. Read the 000 as 50 mΩ maximum, not zero.
Check the series, not the case size, for the rating. Expect the space in the part number. And
if you need the 30 mΩ F-tolerance part, ask, because the export will never show it to you.

Send us your BOM and we will tell you which jumper line each 0 Ω position belongs to, with
the rated current for the part we quote. Or give us one part number and ask us to cross it.

Two things you can do without waiting for a reply. Cross your part — paste a single number or drop in an Excel or CSV of the whole line, and each result names what matches and what does not. And ready stock lists the chip resistor part numbers held in Hong Kong, with an RFQ against any of them.

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