This article discusses the creation of a common-mode current in a typical circuit and explains the effectiveness of a common-mode choke on differential-mode and common-mode currents.
This article investigates the impedance of the three standard passive circuit components (R, L, and C) as well as the frequency response of a PCB trace.
Foundations
Consider the transmission line circuit shown in Figure 1. A sinusoidal voltage source with its source impedance drives a lossless transmission line with characteristic impedance ZC, terminated in... Read More...
Comparatively simple measures can be taken to enhance EMC if a circuit is to be used in a well-known environment. But this becomes more difficult if the module is to be used as universally as possible in differ... Read More...
Every EMI (electromagnetic interference) problem ultimately starts or ends at an electronic circuit. And since electronic components are the building blocks of circuits, it only makes sense to pay attention to the EMI impact of those individual components.
Probably the most important thing to remember about electronic components is that nothing is ideal. Components change values with frequency, current, voltage, and even physical size. And those changes may be nonlinear, adding a new level of complexity. Like a pilot, you need to know the limits so you stay within the envelope of safe performance.
A ferrite bead is a passive device that removes noise energy from a circuit in the form of heat. The bead creates impedance over a broad frequency range that eliminates all or part of the undesired noise energy over that frequency range.