Electronic – What are sacrificial components


The circuit diagram of a board I'm working on has parts labelled as "sacrificial components". These components seem to be pairs of probe points connected via a capacitor, and connected to nothing else.

What are these "sacrificial components"? What are their purpose?

Best Answer

To elaborate on W5VO's comment about offering to the gods. +1 by the way.

Sacrificial for protection

In my experience sacrificial component implies that the part will take some kind of damage and get destroyed in order to prevent some more precious part of the circuit from taking damage. Usually, a sacrificial part is designed so that it's easy to replace. One example, would be a common AGU fuse.

Another example. A certain instrument needs to measure an input with an expensive A/D converter. The input arrives via connector, which is exposed to the outside world. Harm can come through the connector (ESD, overvoltage, reverse polarity). A sacrificial OpAmp buffer in a socketed DIP package can be added between the connector and A/D.


On the other hand, that all doesn't make a lot of sense in the context of O.P., in which sacrificial parts are not connected to anything. How would harm come to them? A snippet of your schematic and even a portion of the PCB layout would help understand your context better.

Sacrificial for fabrication

During fabrication* sacrificial mean that something is destroyed in the process of making the product without becoming a part of the product. Sacrificial material is a part of the fabrication process. Simple example: when you want to drill a hole, you might put a piece of wood on the other side of your part, so that the drill bit doesn't over-penetrate into something important.

* of anything, not just electronics.

May be, this is your case. May be, test points are used for some mechanical purpose. EDA package demands that they have to be connected to something (anything), so they are connected to the dummy capacitor.