A step-up transformer has 80 turns on its primary coil and 1200 turns on its secondary coil. The primary circuit is supplied with an alternating current at 120 V.
Assuming ideal transformer and neglecting losses:
1. Calculate the turns ratio:
turns ratio = N₂ / N₁ = 1200/80 = 15
2. Calculate the output voltage:
output voltage = turns ratio x input voltage = 15 x 120 V = 1800 V
Therefore, the output voltage is 1800 V.
The primary coil of a transformer has 150 turns. It is connected to a 120 V source. Calculate the number of turns on the secondary coil needed to supply the following voltages.
Assuming ideal transformer and neglecting losses:
1. Calculate the turns ratio:
turns ratio = N₂ / N₁
2. Calculate the number of turns on the secondary coil for each required output voltage:
a) For an output voltage of 240 V:
turns ratio = output voltage / input voltage = 240 V / 120 V = 2
N₂ = turns ratio x N₁ = 2 x 150 turns = 300 turns
Therefore, the secondary coil must have 300 turns to supply an output voltage of 240 V.
b) For an output voltage of 12 V:
turns ratio = output voltage / input voltage = 12 V / 120 V = 0.1
N₂ = turns ratio x N₁ = 0.1 x 150 turns = 15 turns
Therefore, the secondary coil must have 15 turns to supply an output voltage of 12 V.
A doorbell requires an effective potential difference of 10 V from a 120 V line.
If the primary coil has 475 turns, how many does the secondary coil have?
The doorbell draws 125 mA of current. What current is in the primary circuit?
Assuming ideal transformer and neglecting losses:
1. Calculate the turns ratio:
turns ratio = output voltage / input voltage = 10 V / 120 V = 0.0833
2. Calculate the number of turns on the secondary coil:
N₂ = turns ratio x N₁ = 0.0833 x 475 turns = 39.575 turns (rounded to 40 turns)
Therefore, the secondary coil must have 40 turns.
3. Calculate the current in the primary circuit using the turns ratio:
current in primary = current in secondary / turns ratio
current in primary = 125 mA / 0.0833 = 1501.5 mA or 1.5015 A (rounded to 3 significant figures)
Therefore, the current in the primary circuit is 1.50 A.
A step-up transformer has 80 turns on its primary coil and 1200 turns on its secondary coil. The primary circuit is supplied with an alternating current at 120.
The current in the secondary circuit is 2.0 A. What current is in the primary circuit?
Assuming ideal transformer and neglecting losses:
1. Calculate the turns ratio:
turns ratio = N₂ / N₁ = 1200/80 = 15
2. Calculate the current in the primary circuit using the turns ratio:
current in primary = current in secondary / turns ratio
current in primary = 2.0 A / 15 = 0.133 A or 133 mA (rounded to 3 significant figures)
Therefore, the current in the primary circuit is 0.133 A or 133 mA.
The power supply in a laptop computer requires an effective voltage of 9.0 V from a 120 V line. If the primary coil has 475 turns, how many does the secondary coil have? A 125 mA current is in the computer. What current is in the primary circuit?
Assuming ideal transformer and neglecting losses:
1. Calculate the turns ratio:
turns ratio = output voltage / input voltage = 9.0 V / 120 V = 0.075
2. Calculate the number of turns on the secondary coil:
N₂ = turns ratio x N₁ = 0.075 x 475 turns = 35.625 turns (rounded to 36 turns)
Therefore, the secondary coil must have 36 turns.
3. Calculate the current in the primary circuit using the turns ratio:
current in primary = current in secondary / turns ratio
current in primary = 125 mA / 0.075 = 1666.67 mA or 1.67 A (rounded to 3 significant figures)
Therefore, the current in the primary circuit is 1.67 A.
To find the voltage across the secondary coil of the step-up transformer, you can use the turns ratio formula.
The turns ratio formula states that the ratio of the number of turns on the primary coil (N1) to the number of turns on the secondary coil (N2) is equal to the ratio of the output voltage (V2) to the input voltage (V1). Mathematically, it can be expressed as:
N1/N2 = V1/V2
Given that the primary coil has 80 turns (N1) and the secondary coil has 1200 turns (N2), and the input voltage (V1) is 120 V, you can rearrange the formula to solve for the output voltage (V2):
V2 = (N2/N1) * V1
Substituting the given values:
V2 = (1200/80) * 120 V
V2 = 1500 V
Therefore, the voltage across the secondary coil of the step-up transformer is 1500 V.