(modular system power supply)
Jonathan Lozano R
Certificate 3 Electrotechnology
A power supply (sometimes known as a power supply unit orPSU) is a device or system that supplies electrical or other types of energy to an output load or group of loads. The term is most commonly applied to electrical energy supplies, less often tomechanical ones, and rarely to others.
Constraints that commonly affect power supplies are the amount of power they can supply, how long they can supply it for without needing some kind of refueling orrecharging, how stable their output voltage or current is under varying load conditions, and whether they provide continuous power or pulses.
The regulation of power supplies is done by incorporatingcircuitry to tightly control the output voltage and/or current of the power supply to a specific value. The specific value is closely maintained despite variations in the load presented to the powersupply's output, or any reasonable voltage variation at the power supply's input. This kind of regulation is commonly categorised as a Stabilized power supply.
A simple AC powered linear power supplyusually uses a transformer to convert the voltage from the wall outlet (mains) to a different, usually a lower voltage. If it is used to produce DC a rectifier circuit is employed either as a single chip,an array of diodes sometimes called a diode bridge or Bridge Rectifier, both for fullwave rectification or a single diode yielding a half wave (pulsating) output. More elaborate configurations rectifythe AC voltage at first to pulsating DC. Then a capacitor smooths out part of the pulses giving a type of DC voltage. The smaller pulses remaining are known as ripple. Because of a fullwaverectification they occur at twice the mains frequency (in USA it's 60 Hz doubled to 120 Hz - or the UK, it's 50Hz, doubled to 100Hz). Finally, depending on the requirements of the load, a linear regulator...