ELECTRONIC CIRCUITS & DEVICES

a rotary converter is a single machine with ___.

• one armature and one field

• two armatures and one field

• one armature and two fields

• two armatures and two fields

a synchronous converter can be started ____.

• by means of a small auxiliary motor

• from AC side as induction motor

• from DC side as DC motor

• any of the above methods

what is the efficiency of full wave rectifier?

• 100%

• 90%

• 80%

• 70%

an unregulated power supply which consist of a transformer, a rectifier and a filter has some characteristics which are as follows EXCEPT one. which is it?

• it has a good voltage regulation

• it is relatively inexpensive

• the output voltage varies with the load

• output voltage depends on input voltage

the ripple factor of a power supply is a measure of ___.

• its filter efficiency

• diode rating

• its voltage regulation

• purity of power output

what is UPS stands for?

• Uninterrupting Power Supply

• Uninterruptible Power Supply

• United Power System

• Uninterruptible Portable Supply

if a transistor is operated in such a way that output current flows for 170 deg. of the input signal, then it is ___ operation.

• class A

• class B

• class C

• class AB

unit of a sound absorption coefficient of materials?

• decibel

• watts

• erg

• sabine

unit of measure of sound intensity level is ___

• watts

• decibel

• erg

• sabine

an SCR (silicon controlled rectifier) behaves as a ___ switch

• bidirectional

• mechanical

• unidirectional

• three-way