Quote Originally Posted by vvti2.0 View Post
Yung cheap avr, ordinary transformer lang laman, yung mamahalin, servo ang laman.
They both have advantages and disadvantages. Servo AVRs have the advantage of being continuously variable. So if your nominal output is 220V, it is able to maintain that to within a volt, even if the input is all over the place. The only disadvantage is that, the servo is very slow in responding to changes from the input voltage. So say if the outlet voltage changed from 230V to 170V then back to 230V in less than a second (a brown-out), a servo AVR wouldn't be able to keep up the regulation. If a computer is attached to it, it would've undoubtedly restarted.

A relay-operated AVR on the other hand can switch instantly. However, it can only do boost and cut in increments of between 10-20V. It means that the actual output voltage could potentially range between 200-250V.

Servo AVRs are ideal if your utility voltage grandually changes theoughout the day. This is typical behavior near industrial areas where heavy electrical machineries exists. The result of such is that, during the day with all the machines running, you may have a nominal 210-220V out of your outlet. But at night, with the equipment turned off, you could see a jump in outlet voltages as high as 260V.