Electrical and Electronics Engineering Interview Questions and Answers
Question - 21 : - How To Reverse The Direction Of Rotation Of Dc Motor?
Answer - 21 : -
To reverse direction of rotation of dc motor, either direction of main field produced by the field winding is reversed or direction of the current passing through the armature is reversed.
By changing the direction of current passing through the field winding,the direction of the main field can be reversed.
Question - 22 : - How To Determine The Number Of Lamps In Final Sub Circuit?
Answer - 22 : -
If it is decided the current rating and already cable installed according to the rating of final sub circuit. and we want to know that how many light point will be on this final sub circuit.
Suppose for a normal lighting in a home,office or hall, the current rating of sub circuit or final sub circuit is 5Amp and supply Voltage is 220 Volts. then how many 100 Watt Lamps we can instal on that specific sub circuit. We can find the number of lamps by using this formula.
Question - 23 : - What Are The Main Difference Between Active And Passive Components?
Answer - 23 : -
The Main Difference between Active and Passive Components
Active Components: Those devices or components which produce energy in the form of Voltage or Current are called as Active Components
For Example: Diodes Transistors SCR etc…
Passive Components: Those devices or components which store or maintain Energy in the form of Voltage or Current are known as Passive Components
For Example: Resistor, Capacitor, Inductor etc…
Question - 24 : - What Is Capacitance?
Answer - 24 : -
Capacitance (C): Capacitance is the amount of electric charge moved in the condenser (Capacitor), when one volt power source is attached across its terminal.
Question - 25 : - What Is Capacitance Equation?
Answer - 25 : -
Capacitance Equation:
C=Q/V
Where,
- C=Capacitance in Farads (F).
- Q=Electrical Charge in Coulombs.
- V=Voltage in Volts.
Question - 26 : - How Capacitor Works?
Answer - 26 : -
Working and Construction of a capacitor :
Whenever voltage is applied across its terminals, (Also known as charging of a capacitor) current start to flow and continue to travel until the voltage across both the negative and positive (Anode and Cathode) plates become equal to the voltage of the source (Applied Voltage). These two plates are separated by a dielectric material (such as mice, paper, glass, etc. which are insulators), which is used to increase the capacitance of the capacitor.
When we connect a charged capacitor across a small load, it starts to supply the voltage (Stored energy) to that load until the capacitor fully discharges.
Capacitor comes in different shapes and their value is measured in farad (F). Capacitors are used in both AC and DC systems
Question - 27 : - What Is The Role Of Capacitor In Ac And Dc Circuit?
Answer - 27 : -
Role of Capacitor in AC Circuits: In an AC circuit, capacitor reverses its charges as the current alternates and produces a lagging voltage (in other words, capacitor provides leading current in AC circuits and networks).
Role and Performance of Capacitor in DC Circuit.
In a DC Circuit, the capacitor once charged with the applied voltage acts as an open switch.
Question - 28 : - Why We Can’t Store Ac In Batteries Instead Of Dc.or Can We Store Ac In Batteries Instead Of Dc?
Answer - 28 : -
We cannot store AC in batteries because AC changes their polarity up to 50 (When frequency = 50 Hz) or 60 (When frequency = 60 Hz) times in a second. Therefore the battery terminals keep changing Positive (+ve) becomes Negative (-Ve) and vice versa, but the battery cannot change their terminals with the same speed so that’s why we can’t store AC in Batteries.
in addition, when we connect a battery with AC Supply, then It will charge during positive half cycle and discharge during negative half cycle, because the Positive (+ve) half cycle cancel the negative (-Ve) half cycle, so the average voltage or current in a complete cycle is Zero. So there is no chance to store AC in the Batteries.
Question - 29 : - What Is An Instrumentation Amplifier?
Answer - 29 : -
An instrumentation (or instrumentational) amplifier is a type of differential amplifier that has been outfitted with input buffer amplifiers, which eliminate the need for input impedance matching and thus make the amplifier particularly suitable for use in measurement and test equipment.
Question - 30 : - Define Modulation. ?
Answer - 30 : -
In electronics and telecommunications, modulation is the process of varying one or more properties of a periodic waveform, called the carrier signal, with a modulating signal that typically contains information to be transmitted.