Transformers

We are given a transformer that steps up the voltage from 22 V to 220 V, and the load resistance is 110 . We need to find the current drawn by the primary coil of the transformer. Step 1: Use the Transformer Equation The voltage and current relationship for an ideal transformer is given by: Where: - is the primary voltage, - is the secondary voltage, - is the current in the primary coil, - is the current in the secondary coil. Given: - , - . We need to find the current in the primary coil . Step 2: Find the Secondary Current First, we calculate the secondary current using Ohm’s law: Where is the load resistance. Given: - , - . Substitute the values: Step 3: Use the Transformer Equation to Find the Primary Current Now, using the transformer equation: Substitute the values: Solving for : Thus, the current drawn by the primary coil is 20 (A) Therefore, the correct answer is Option (A): 20 (A)

In this problem, we are given a transformer that steps down 330 V to 33 V, and the device has an impedance of 110 . We need to find the current drawn by the primary coil.
Step 1: Use the formula for the current in the secondary coil
We know that the current in the secondary coil is given by Ohm's law: where: - is the current in the secondary coil, - is the voltage in the secondary coil (33 V), - is the impedance of the device (110 ). Substitute the given values:
Step 2: Use the transformer relationship
For an ideal transformer, the relationship between the primary and secondary coils is given by: where: - is the primary voltage (330 V), - is the secondary voltage (33 V), - is the current in the primary coil, - is the current in the secondary coil. Rearranging the formula to find : Substitute the known values: Thus, the current drawn by the primary coil is 0.03 A.