# 34 Lecture

## Transformers

Transformers are a crucial component in many electrical systems, used for the transmission and distribution of electrical power as well as in various electronic devices.

## Important Mcq's Midterm & Finalterm Prepration Past papers included

What is the primary function of a transformer?

A. To convert DC to AC

B. To amplify electrical signals

C. To transfer electrical energy through electromagnetic induction

D. To protect electrical devices from power surges

What is the turns ratio of a transformer?

A. The ratio of power output to power input

B. The ratio of the number of turns in the secondary winding to the number of turns in the primary winding

C. The ratio of voltage to current

D. The ratio of resistance to capacitance

What is the efficiency of a transformer?

A. The ratio of the number of turns in the primary winding to the number of turns in the secondary winding

B. The ratio of the power output to the power input

C. The ratio of the voltage output to the voltage input

D. The ratio of the current output to the current input

How are transformers used in power systems?

A. To convert DC to AC

B. To amplify electrical signals

C. To transfer electrical energy at high voltages and low currents

D. To regulate the flow of current through a circuit

What is the maximum power rating of a transformer?

A. The maximum amount of power that can be input into a transformer

B. The maximum amount of power that can be output from a transformer

C. The maximum amount of power that a transformer can handle before becoming damaged

D. The maximum amount of power that a transformer can transfer through electromagnetic induction

What is the frequency response of a transformer?

A. The ability of a transformer to transmit signals of different frequencies

B. The maximum frequency that a transformer can handle

C. The minimum frequency that a transformer can handle

D. The frequency at which a transformer resonates

What are step-up transformers used for?

A. To increase the voltage level of an electrical signal

B. To decrease the voltage level of an electrical signal

C. To amplify electrical signals

D. To regulate the flow of current through a circuit

What are isolation transformers used for?

A. To match the impedance of audio devices

B. To protect electrical devices from power surges

C. To transfer electrical energy between circuits

D. To provide electrical isolation between two circuits

What is the purpose of a transformer core?

A. To conduct electricity

B. To provide mechanical support to the transformer

C. To focus the magnetic field and increase the efficiency of the transformer

D. To regulate the flow of current through a circuit

What is a tap changer in a transformer?

A. A device used to change the frequency of the electrical signal

B. A device used to adjust the voltage level of the electrical signal

C. A device used to switch the transformer on and off

D. A device used to match the impedance of audio devices

## Subjective Short Notes Midterm & Finalterm Prepration Past papers included

What is the primary function of a transformer?

Answer: The primary function of a transformer is to transfer electrical energy from one circuit to another through electromagnetic induction.

What is the turns ratio of a transformer?

Answer: The turns ratio of a transformer is the ratio of the number of turns in the secondary winding to the number of turns in the primary winding.

How is the voltage level of an electrical signal transformed by a transformer?

Answer: The voltage level of an electrical signal is transformed by a transformer through the principle of electromagnetic induction. When an alternating current flows through the primary winding, it creates a magnetic field that induces a voltage in the secondary winding.

What is the efficiency of a transformer?

Answer: The efficiency of a transformer is the ratio of the power output to the power input. A transformer with high efficiency will convert a large proportion of the electrical energy supplied to it into useful output power.

How are transformers used in power systems?

Answer: Transformers are used in power systems to step up or step down the voltage level of electrical signals to reduce power losses during transmission over long distances and for distribution to consumers.

What is the maximum power rating of a transformer?

Answer: The maximum power rating of a transformer is the maximum amount of power that it can handle before it becomes damaged. The rating depends on factors such as the size of the magnetic core, the thickness of the winding wire, and the quality of the insulation.

How are transformers used in audio equipment?

Answer: Transformers are used in audio equipment to match the impedance of audio devices and to isolate audio signals from other electronic components.

What is the frequency response of a transformer?

Answer: The frequency response of a transformer refers to its ability to transmit signals of different frequencies. Transformers are designed to work within specific frequency ranges.

What are some limitations of transformers?

Answer: Limitations of transformers include their maximum power rating, their frequency response, and the effects of factors such as the quality of the magnetic core and the design of the winding.

Why are transformers important in modern electrical engineering?

Answer: Transformers are important in modern electrical engineering because they are a critical component in many electrical systems and are used for the transmission and distribution of electrical power as well as in various electronic devices. They help to maintain the efficiency of power systems and ensure the proper functioning of electronic devices.

### Transformers

Transformers are a crucial component in many electrical systems, used for the transmission and distribution of electrical power as well as in various electronic devices. A transformer is an electrical device that transfers electrical energy from one circuit to another through electromagnetic induction. This means that it is used to transform the voltage level or current level of an electrical signal from one circuit to another, without any direct electrical connection between the two circuits. The basic principle of a transformer is that it consists of two coils of wire wound around a common magnetic core. These coils are called the primary and secondary windings. The primary winding is connected to the source of electrical energy, while the secondary winding is connected to the load. The transformer operates on the principle of Faraday’s law of electromagnetic induction, which states that when there is a change in the magnetic flux in a coil of wire, an electromotive force (EMF) is induced in the coil. When an alternating current (AC) flows through the primary winding, it creates a magnetic field around the primary coil, which in turn induces an EMF in the secondary winding. The magnitude of the induced EMF in the secondary winding is proportional to the ratio of the number of turns in the secondary winding to the number of turns in the primary winding. This is known as the turns ratio of the transformer. Transformers are commonly used in power systems for the transmission and distribution of electrical energy. High-voltage power generated at a power station is stepped up by transformers to reduce power losses during transmission over long distances. The voltage is then stepped down again at substations for distribution to consumers. In this way, transformers play a crucial role in the efficient delivery of electrical power. In addition to their use in power systems, transformers are also used in a wide range of electronic devices. For example, they are used in power supplies to convert high-voltage AC to low-voltage DC for electronic circuits. Transformers are also used in audio equipment to match the impedance of audio devices and to isolate audio signals from other electronic components. One of the key characteristics of a transformer is its efficiency, which is the ratio of the power output to the power input. A transformer with high efficiency will convert a large proportion of the electrical energy supplied to it into useful output power, while minimizing energy losses due to heat and other factors. This is important in many applications, especially in power systems where losses in transformers can add up to significant amounts of wasted energy. Another important characteristic of transformers is their frequency response. This refers to the ability of a transformer to transmit signals of different frequencies. Transformers are designed to work within specific frequency ranges, and their performance can be affected by factors such as the quality of the magnetic core and the design of the winding. Transformers also have certain limitations, such as their maximum power rating, which is the maximum amount of power that they can handle before they become damaged. The maximum power rating of a transformer depends on factors such as the size of the magnetic core, the thickness of the winding wire, and the quality of the insulation. In summary, transformers are a critical component in many electrical systems, used for the transmission and distribution of electrical power as well as in various electronic devices. They operate on the principle of electromagnetic induction and are designed to transform the voltage or current level of an electrical signal from one circuit to another. Transformers are important in maintaining the efficiency of power systems and ensuring the proper functioning of electronic devices. As such, they are an essential component of modern electrical engineering.