Question

Examples and describe voltage, current, and phase angle.

Describe power and resonance in ac circuits.

Examples in daily life and explain how transformers work.

PLEASE DO NOT WRITE IT BY HAND

Answer 1

Voltage is defined as the electromotive force or the electric potential energy difference between two points (often within the context of an electrical circuit) per unit of charge, expressed in volts (V). Voltage, along with current and resistance, is used to describe the behavior of electrons.example of Voltage is one of those ubiquitous aspects of everyday life that tends to get overlooked. We readily flip switches to turn on lights or press buttons to activate appliances, all without giving it much of a second thought. Electricity is everywhere, and it has always been that way for the vast majority of us. But when you give yourself a moment to think, you might wonder about this fundamental that powers the entire world. It may seem a little abstract, but voltage is really as easy to understand.

Current :- An electric current is a flow of electric charge. In electric circuits this charge is often carried by moving electrons in a wire. It can also be carried by ions in an electrolyte, or by both ions and electrons such as in an ionised gas

(plasma).example of current It cau Joule heating, which creates light in incandescent light bulbs. They also create magnetic fields, which are used in motors, inductors and generators.the relationship between voltage ,resistance and current are v=IR that's called ohms law.

Phase angle :-n the context of phasors, phase angle refers to the angular component of the complex number representation of the function. The notation

for a vector with magnitude (or amplitude) A and phase angle ?, is called angle notation.

This notation is frequently used to represent an electrical impedance. In this case, the phase angle is the phase difference between the voltage applied to the impedance and current driven through it.

Power:- Electrical power is the rate at which electrical energy is converted to another form, such as motion, heat, or an electromagnetic field. The common symbol for power is the uppercase letter P. The standard unit is the watt,symbolized by W. In utility circuits, the kilowatt (kW) is often specified instead;1 kW = 1000 W.

Electric power is usually produced by electric generators, but can also be supplied by sources such as electric batteries.

Resonance in ac circuits :- Originally Answered: What is resonance in an AC circuit?

Resonance is the condetion in AC circuit when the phase of voltage and the phase of current are exactly same. This means that the phase difference between the voltage and current is zero. In simple words, the voltage and current rises and falls on the same time and only resistors are considered in the overall impedance of the circuit.

In an AC circuit the resonance is achived when the inductive reactance (XL) is equal to the capacitive reactance (XC) and due to which the overall impedance is turned out to be equal to R.

Z^2 = R^2 + (ZL - ZC)^2

For ZL = ZC

Z = R

This will not allow the phase difference between the current and voltage in the circuit.

For finding the Resonant frequency, the frequency at which resonance is occured following formula is used.

ZL = ZC

2?fL = 1/2?fC

f^2 = 1/4LC?^2

f = 1/2??LC

How transformers work ? Answer is

Transformers work on the principle of mutual induction. It is nothing but a magnetically coupled circuit. It consists of two windings (primary and secondary) which are wound on an iron core. These windings have self inductance and mutual inductance. When voltage is applied across one coil, flux is generated in the iron core (iron has high magnetic permeability, hence it is used so that no flux will be wasted i.e., all the flux will be linked to other winding). This amount of flux linked with the secondary winding induces proportionate voltage in it and if there is a closed path provided there will be a current flow in the secondary winding. The amount of voltage induced in secondary winding depends on the flux linkage which in turn depends on the turns ratio. Hence the final relation is
               (V1/V2) = (N1/N2)
where V1 = voltage across primary coil
           V2 = voltage across secondary coil
           N1 = no. of turns in primary coil
           N2 = no. of turns in secondary coil
         By looking at the relation we can say if some voltage is fed to one coil, we get a different voltage at another coil. That is the main purpose of a transformer: to step-up (to increase) or to step-down (to decrease) AC voltages. It should not be operated with DC voltages because inductance will be shorted in DC (since the current is constant) and high current flows through the coils causing damage to the transformer.