A transformer which can produce 8V from a 240v a.c. supply, has an efficiency of 80%. If the current in the secondary coil is 15A, calculate the current in ...

A transformer which can produce 8V from a 240v a.c. supply, has an efficiency of 80%. If the current in the secondary coil is 15A, calculate the current in the primary coil.

Answer Details

To solve this problem, we can use the formula for power: Power (in watts) = Voltage x Current Since the transformer has an efficiency of 80%, it means that 80% of the input power is transferred to the output. The remaining 20% is lost as heat. Therefore, we can say that: Output Power = Input Power x Efficiency We know the output voltage is 8V, and the output current is 15A. So, the output power can be calculated as: Output Power = 8V x 15A = 120W Substituting the values in the formula for efficiency, we get: 120W = Input Power x 0.80 Input Power = 120W/0.80 = 150W Now, we can calculate the input current using the formula: Input Power = Input Voltage x Input Current Substituting the values, we get: 150W = 240V x Input Current Input Current = 150W/240V = 0.625A Therefore, the current in the primary coil is 0.625A.