Layout design for NPO capacitors


Some NPO (Non-POlarized) capacitors may have a stripe on their package. Since this can’t be a polarization indication, you might wonder what it means.

A capacitor is made of two conductive elements separated by a non conductive element. In cylindric capacitors (both radial and axial), there is a central core for one conductive element, and an outer shell that makes the second, with some non-conductive substrate in the middle.

The mark on an NPO point to the outer shell. This can be interesting if you need an end of your cap to be grounded. Grounding the outer shell provides isolation from EMI and prevents noise getting in the capacitor.

Check out the layout design tips and tricks that can take advantage of this.

Source: Hack a Day.


Ground design considerations on EDN

Here is a series of very interesting articles on how to handle grounding in a PCB design, to avoid hum and EMI, especially when working with both analog and digital (mixed signal) chips.

Other articles in the same topic:

If you’re into electronics and PCB design, check out where these articles come from, it’s a real gold mine of information and tips!