Understanding Transformers

This video tutorial explains the concept of electrical transformers, focusing on their ability to step up or step down AC voltage. It covers the basic components of transformers, such as primary and secondary coils, and the principle of power conservation. The video includes example problems to illustrate calculations involving voltage, current, and resistance, as well as determining transformer efficiency.

What is the primary function of a transformer?

• To convert AC to DC

• To increase or decrease AC voltage

• To store electrical energy

• To generate electricity

In a step-up transformer, how does the number of turns in the secondary coil compare to the primary coil?

• The secondary coil has fewer turns

• The secondary coil has more turns

• Both coils have the same number of turns

• The number of turns is irrelevant

What happens to the current in a transformer when the voltage is increased?

• The current becomes zero

• The current increases

• The current decreases

• The current remains the same

Which equation represents the relationship between the turns ratio and voltage ratio in a transformer?

• NP/NS = IP/IS

• NP/NS = VS/VP

• NP/NS = VP/VS

• NP/NS = IS/IP

In the first example problem, what is the calculated output voltage?

• 54 volts

• 12 volts

• 180 volts

• 120 volts

How is the input current calculated in the first example problem?

• By dividing the output current by the turns ratio

• By adding the output current to the turns ratio

• By multiplying the output current by the turns ratio

• By subtracting the output current from the turns ratio

In the second example problem, what is the input voltage of the transformer?

• 20 volts

• 100 volts

• 5 volts

• 12 volts

What type of transformer is described in the second example problem?

• Step-down transformer

• Step-up transformer

• Isolation transformer

• Auto transformer

How many secondary turns are there in the second example problem?

• 600 turns

• 480 turns

• 200 turns

• 1000 turns

What is the efficiency of the transformer in the third example problem?

• 95%

• 100%

• 99%

• 97.2%