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I recently got a pack of different value resistors, but some of them were zero ohms. Is there any purpose in using 0 ohm resistors?

Wesley Lee
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Nathan Jiang
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    option jumper ... – jsotola Jun 19 '21 at 21:36
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    Another reason might be that pick-and-place machines can handle them like normal resistors - especially for SMD parts. – ErikR Jun 19 '21 at 21:42
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    @WesleyLee, your edit is incorrect. Small 'o' for ohm. SI units named after a person have their symbols capitalised but are lowercase when spelt out. 'V' for volt, 'A' for ampere, 'W' for watt, 'K' for kelvin (and 'k' for kilo), etc. See SI standards. Can you undo? – Transistor Jun 19 '21 at 22:03
  • @Transistor - Just undid the last one on the title. Thanks for pointing that out! – Wesley Lee Jun 19 '21 at 22:05
  • We drop zero-ohm resistors at strategic locations where we think there might be some high frequency noise (EMI) problems. If the real PCB proves to have issues, the spots to place small EMI-absorbing ferrite beads is already there. Zero ohm resistors (most resistors really) cost almost nothing in mass production quantities - Like about 1/20th of a penny - Even using thousands of them, it's far far less than we'd spend re-spinning a PCB to add a ferrite where one is needed but no accommodation was made for it. – Kyle B Jun 20 '21 at 06:16

2 Answers2

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Yes, they have multiple purposes.

They can be used for configuring one board between options.

They are also useful when a signal needs to jump over tracks to for example keep a PCB design single sided.

And sometimes, a PCB can be designed without knowing if a resistor is needed or not, so a place for it is drawn and it can be replaced with other value in production if necessary.

Justme
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Yes, zero Ohm “resistors” are very useful. When strategically place within a design and board layout, they can be used to enable or disable specific circuit options. You can really think of them as semi-permanent switches. When they are not soldered into the circuit, the circuit is broken and not enabled. When they are soldered into place, they allow current to flow through and enabling the circuit option.

For example, you may want the option of a general purpose output pin from a microcontroller to light an LED, or enable a motor. Using zero Ohm resistors in strategic places you can remove a resistor to disable ability for the microcontroller to enable the motor drive transistor, and place a resistor to enable the microcontroller to drive the LED transistor. Reciprocally, you can place the resistor to enable the motor drive transistor and remove the ability to drive the LED.

This is usually done to allow flexibility in the use of the PCB, or for experimental circuits. Their use can prevent the costly need of building multiple boards with only very slight differences.

TimB
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    SI standard is that all unit names, when written out, are lowercase. So, "ohm", not "Ohm", unless you're talking about the person the unit's named after. – Hearth Jun 20 '21 at 00:10
  • Hi. I am interested in this. Can you provide a reference for me? – TimB Jun 21 '21 at 03:12
  • See for instance [the NIST guidelines for scientific publications.](https://www.nist.gov/pml/weights-and-measures/writing-metric-units) – Hearth Jun 21 '21 at 13:00