Transformer Calculations

• What is the purpose of transformers in electricity supply?

  Transformers change the potential difference of an electricity supply.
• How do step-up transformers increase potential difference?

  They have more turns on the secondary coil than on the primary coil.
• What is the function of step-down transformers?

  They decrease the potential difference because they have fewer turns on the secondary coil.
• What do the variables \( v \), \( n \), and \( i \) represent in the transformer equations?

  \( v \) is the potential difference, \( n \) is the number of turns on the coil, and \( i \) is the current.
• What do the subscripts \( p \) and \( s \) stand for in the transformer equations?

  \( p \) stands for primary coil and \( s \) stands for secondary coil.
• If a transformer has 18 turns on its primary coil and 54 turns on its secondary coil, what is the ratio of turns?

  The ratio of turns is \( \frac{18}{54} \) or \( \frac{1}{3} \).
• Given an input potential difference of 45 volts, how do you calculate the output potential difference using the transformer equations?

  You use the equation \( \frac{v_p}{v_s} = \frac{n_p}{n_s} \).
• If a transformer has 18 turns on the primary coil and 54 turns on the secondary coil with an input potential difference of 45 volts, what is the output potential difference?

  The output potential difference is 135 volts.
• If the input current is 12 amps, how do you find the output current using the transformer equations?

  You use the equation \( v_p \times i_p = v_s \times i_s \).
• If the input current is 12 amps and the output potential difference is 135 volts, what is the output current?

  The output current is 4 amps.
• What are the two main equations used in transformer calculations?

  1. \( \frac{v_p}{v_s} = \frac{n_p}{n_s} \)
  2. \( v_p \times i_p = v_s \times i_s \)