Explain the working of transformers, Physics

Assignment Help:

Explain the working of Transformers

A transformer often uses a core, which looks like a square donut of iron, to change the voltage applied to the primary coil to a new larger or smaller voltage on the secondary coil.

1160_Transformers 1.png

The current caused by the voltage in the primary coil generates a magnetic field, which extends to all parts of the iron. This extended magnetic field then causes a voltage in the secondary coil, but if the primary coil has fewer loops than the secondary, the voltage out will be larger than the applied voltage.

1939_Transformers 2.png

Where Vs is the voltage in the secondary coil in volts and Vp is the voltage in the primary coil in volts. If both primary and secondary coils have an equal number of loops, the voltages will be the same on both sides. If the secondary coil has more loops than the primary, the voltage out will be more than the applied voltage, and the transformer is a step-up transformer. If the primary coil has more turns than the secondary, the voltage out will be less than the applied voltage, and the transformer is a step-down transformer.

2325_Transformers 3.png

Since the energy (and therefore the power) in has to equal the energy (or power) out, conservation of energy still holds, and the power in the primary Pp  =  Ip  Vp  must equal Ps  =  Is  Vs. While the voltage increases,

Ip  Vp  = Is  Vs

so that the current in the secondary, Is, must decrease to have the same product. If this is an ideal transformer, so that it loses no energy, the previous equation will help calculate Is if Vs is known. However, if the transformer is real and has less than 100% efficiency,

1813_Transformers 4.png

where Power is in watts, and efficiency is a fraction less than one or a percent out of 100%. The rest of the energy is turned to heat through the resistance of the wire, magnetization and demagnetization of the core, and eddy currents in the core.

Example- A step-down transformer is used to change 120 V AC from the wall plug to 12V AC. If the secondary coil has 100 turns and supplies 250 mA of current...

374_Transformers 5.png

  1. How many turns are in the primary coil?
  2. What is the current in the primary coil (assuming the transformer is 100% efficient)?
  3. How much power is transformed if the transformer is ideal? 
  4. How much power if the transformer is only 80% efficient? 
  5. What is the current in the primary coil if it is 80% efficient? 

How much heat would it generate at 80% efficiency?

2317_Transformers 6.png

All of the examples in this section - cathode ray tubes, oscilloscopes, monitors, televisions, motors, generators and transformers - depend on the relationships among magnetic fields, electric currents and wires, and electromagnets.


Related Discussions:- Explain the working of transformers

Motion in one dimension, an object moves along the x axis according -to the...

an object moves along the x axis according -to the equation x(t)=(3t^2-2t+3)m .determine (a) the average speed b/n t=2sec and t=3sec,(b) the instantaneous speed at t= 2s and t=3s (

Bernoullis theorem, Why there are two propellers in helicopter

Why there are two propellers in helicopter

Find total acceleration vector - tangential velocities, 1. Krusty the Clown...

1. Krusty the Clown and Sideshow Bob have covered themselves in velcro, and shot themselves out of a large cannon so that they stick to a huge rotating velcro wheel (don't try this

Define the terms threshold frequency, Define the terms threshold frequency ...

Define the terms threshold frequency and stopping potential in relation to the phenomenon of photoelectric effect. How is the photoelectric current affected on enhancing the (i)

Explain process of resonance, Resonance: When the frequency of driving...

Resonance: When the frequency of driving force becomes equivalent to the natural frequency of an oscillating system, the driving force gives maximum energy and the oscillating

Tension in a string, two blocks of mass 2kg and 4 kg are held together by a...

two blocks of mass 2kg and 4 kg are held together by a string force of 10N is applied on 2kg and 20N on 4kg find the tension in the string connected between two blocks

FREE FALL, CAN YOU GIVE SOME EXAMPLE OF FREE FALL ACTIVITIES

CAN YOU GIVE SOME EXAMPLE OF FREE FALL ACTIVITIES

Explain frequency, Frequency The number of vibration done per second by...

Frequency The number of vibration done per second by an oscillation body is known its frequency. It is denoted by V. The S.I unit is Hz. V=1/T

Physics, the magnitude and direction of acceleration of body both are const...

the magnitude and direction of acceleration of body both are constant will the body moves in straight line

hypothesize the basic short-run and long-run, Choose and research an indus...

Choose and research an industry where there has been a pattern of change in a particular market model (monopoly, oligopoly, etc.). Write a four to five (4-5) page paper in which

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd