Bypassing: Diverts unwanted common-mode RF energy from components or
cables. This is essential in creating a AC shunt to remove undesired energy from
entering susceptible areas in addition to providing other functions of filtering.
Bulk: Used to maintain constant DC voltage and current to components when all
signal pins switch simultaneously under maximum capacitive load. It also prevents
power dropout due to dI/dt current surges generated by components.
An ideal capacitor has no losses in its conductive plates and dielectric. An ideal
capacitor does not exist, but inductance and resistance is always present due to
physical structure and connection to other circuitry.