Pocket EMC Debug Probe V2

This is a work in progress guide for the assembly and use of the Version 2 “Pocket EMC Debug Probe” from Unit 3 Compliance.

Whilst this page is being written, you can also refer to this page for the previous version which has much of the information that you need.

 

V2 pocket EMC debug probe PCB - near field probe set - board front V2 pocket EMC debug probe PCB - near field probe set - board rear

 

Introduction

A short introduction to near field probes and their uses.

 

Assembly Guide

Components required (0805 resistors, R1 = 470R, R2 = 10k, gives 450 ohm parallel combination, required for the 10:1 into a 50 ohm input, capacitor 1nF, C0G/NPO dielectric, 50V)

Sourcing SMA edge mount female connectors (RS, eBay)

Recommendations for the probing pin (socket strip or a bit of wire)

Suitable ferrite cores for the current transformer

90 degree options for the B-field loop probe and E-field capacitive probe (on E-field probe snap off – scrape copper on each side of slot before you snap off the end to enable soldering)

 

Usage

Narrow down emissions from a PCB by scanning over the surface and looking for noisy traces

Don’t just use the B-field probe, the E-field probe is just as important. Both will respond differently.

Use the current probe attachment to check for noisy cables

Narrow down to individual traces using the high bandwidth probe