A voltage of 120v a.c is supplied to a calculator which uses only 24v. What type of transformer is required? If the resistance is 10 ohms, calculate the current in the secondary and primary circuits of the calculator
To step down the voltage from 120V to 24V, a step-down transformer is required.
To calculate the current in the secondary circuit of the calculator, we can use Ohm's Law, which states that I = V/R.
I (secondary) = 24V / 10 ohms
I (secondary) = 2.4 amps
As for the primary circuit, we can use the equation P = IV to find the power consumed in the secondary circuit. Since transformers are generally assumed to have close to 100% efficiency, the power consumed in the primary circuit should be the same.
P = IV
P (secondary) = 24V x 2.4A
P (secondary) = 57.6 watts
Therefore, the current in the primary circuit of the calculator can be calculated using the equation P = IV.
I (primary) = 57.6 watts / 120V
I (primary) = 0.48 amps