Ease of Use PC Ease of Use PC: this is an initiative proposed by the computer industry to produce personal computers that allow for the following: faster out-of-box setup, simpler operation for first time users, simpler upgradeability and increased reliability. These computers are meant to attract more first-time users with little or no computer experience.
Efficiency The ratio of total output power to input power, expressed in percent. This is normally specified at full load and nominal input voltage. Efficiency = Pout / Pin
Electronic Load An electronic device designed to provide a load to the outputs of a power supply, usually capable of dynamic loading, and frequently programmable or computer controlled.
EMC - Electromagnetic Compatibility The requirement for electromagnetic emissions and susceptibility dictated by the physical environment and regulatory governing bodies in whose jurisdiction a piece of equipment is operated.
EMI - ElectroMagnetic Interference EMI usually refers to unwanted electrical noise present on a power line. This noise may "leak" from the power lines and affect equipment that isn't even connected to the power line. Such "leakage" is called a magnetic field. Magnetic fields are formed when unwanted noise voltages give rise to noise currents. Such noise signals may adversely affect electronic equipment and cause intermittent data problems. EMI protection is provided by placing noise filters on the AC power line. The filter reduces the noise voltage on the protected line, and by doing so also eliminates the magnetic fields of noise generated by the protected line. Noise signals that act over a significant distance are called RFI (Radio Frequency Interference). Equipment power cords and building wiring often act as antennas to receive RFI and convert it to EMI. Electromagnetic interference (EMI) is the noise generated by the switching action of the power supply. Conducted EMI, that portion reflected back into the power line, is normally controlled with a line filter. Radiated EMI, that portion which is radiated into free space, is suppressed by enclosing the circuitry in a metal case. The FCC governs conducted and radiated emission levels.
Emissions Electromagnetic radiation emitted into the atmosphere from the power supply. Conducted is that energy sent down the AC line cord; radiated is sent into the air. Adaptors must meet both but many open frame switchers are only rated for conducted (the assumption being that they will be placed into the customer's box).
ESR - Equivalent Series Resistance The value of resistance in series with an ideal capacitor which duplicates the performance characteristics of a real capacitor.