EMC Concepts Explained

Consider a spherical capacitor consisting of two concentric, conducive spheres separated by a dielectric.

Consider a two-sided PCB with a single trace on top and full copper ground plane on the bottom.

Reducing the duty cycle (the pulsewidth) reduces the low-frequency spectral content of the waveform, but does not affect the high-frequency content.

When two circuits are in the vicinity of one another, a signal propagating in one circuit can induce a signal in another circuit, due to capacitive (electric field) and/or inductive (magnetic field) coupling between the circuits. This phenomenon is referred to as crosstalk.

In this article, we consider the effects of a discontinuity along the transmission line which occurs when the transmission line characteristic impedance changes.

Consider a transmission line of length driven by a constant voltage source with a source resistance, and terminated by a resistive load.