Post by thread:Zero Ohm Resistor

When I first saw a zero ohm resistor, I thought it was silly too, but here is the way I saw it used. It was used to choose a setting. At the node, there was a real resistor tied to +5, a zero ohm to ground. With the zero ohm resistor, the node a logic 0. If one wants a certain setting, you cut the resistor to make the node a logic 1. The zero ohm resistor makes the node easier to identify on the board. Think of it as a dip switch you can only set once. Now saying this, I could never find a reason why one would want a surface mount zero ohm resistor. -Edwin

> > Now saying this, I could never find a reason why one would want a > surface mount zero ohm resistor. > > -Edwin > For the same reason, using a handful of zero ohm resistors, one pcbd may be able to be used for several different products or versions of a product by simply changing the pick and place program. Just think - if every trace was made of zero ohm resistors, you'd never need to do another board change! :) Also, designing a few zero ohm resistors into a product with thoughts of future revisions or potential pitfalls can make a product revision much more painless by (potentially) avoiding a new pcbd layout. Granted, this is a luxury that probably can't be afforded in high volume designs, but into the 10's of thousands it can payoff. -mike spam_OUTmfahrionTakeThisOuTbb-elec.com

In a message dated 96-10-11 16:15:45 EDT, you write: > Now saying this, I could never find a reason why one would want a > surface mount zero ohm resistor. Think of it as a configuration switch set once at pcb assembly time. Mark A. Corio Rochester MicroSystems, Inc. 200 Buell Road, Suite 9 Rochester, NY 14624 Tel: (716) 328-5850 --- Fax: (716) 328-1144 http://www.frontiernet.net/~rmi/ ***** Designing Electronics For Research & Industry *****

> > When I first saw a zero ohm resistor, I thought it was silly too, but > here is the way I saw it used. It was used to choose a setting. At > the node, there was a real resistor tied to +5, a zero ohm to ground. > With the zero ohm resistor, the node a logic 0. If one wants a > certain setting, you cut the resistor to make the node a logic 1. The > zero ohm resistor makes the node easier to identify on the board. > Think of it as a dip switch you can only set once. > > Now saying this, I could never find a reason why one would want a > surface mount zero ohm resistor. Used all the time.. They allow different configurations of a board simply by changing the load tape for the SMD placement machines (i.e. same PCB used). In some boards they allow a jump over a track without having to use an extra pair of vias - useful on simple single sided boards. Adrian.

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> From: Adrian Kennard <cut> > > Now saying this, I could never find a reason why one would want a > > surface mount zero ohm resistor. > > Used all the time.. They allow different configurations of a board > simply by changing the load tape for the SMD placement machines (i.e. > same PCB used). In some boards they allow a jump over a track without having > to use an extra pair of vias - useful on simple single sided boards. > > Adrian. > Not only on simple single sided boards. We have used them on a high speed (1GHz) board where the extra capacitance and track length of going through 2 vias can make a big difference! Gary. -------------------------------------------- Email: .....Gary.FowlerKILLspam@spam@dsto.defence.gov.au Phone: +61 8 8259 5767 Fax: +61 8 8259 5672 Defence Science & Technology Organisation PO Box 1500, Salisbury, South Australia 5108 --------------------------------------------