Subelement C: Components— Topic 21: Transformers
Question 3-21C3
Element 3 (GROL)A transformer primary of 2250 turns connected to 120 VAC will develop what voltage across a 500-turn secondary?
Explanation
Transformers operate on the principle of electromagnetic induction, and the voltage transformation ratio is directly proportional to the turns ratio of their primary and secondary windings. This relationship is expressed by the formula:
$V_s / V_p = N_s / N_p$
Where:
* $V_s$ = Secondary voltage
* $V_p$ = Primary voltage
* $N_s$ = Number of turns in the secondary coil
* $N_p$ = Number of turns in the primary coil
Given:
* $V_p = 120$ VAC
* $N_p = 2250$ turns
* $N_s = 500$ turns
Rearranging the formula to solve for $V_s$:
$V_s = V_p * (N_s / N_p)$
$V_s = 120 * (500 / 2250)$
$V_s = 120 * (0.2222...)$
$V_s = 26.666...$
$V_s \approx 26.7$ volts
This is a step-down transformer since the secondary has fewer turns than the primary, resulting in a lower secondary voltage. Options B and C are incorrect as they suggest a significantly higher (step-up) voltage, and option D is incorrect because it is too low given the turns ratio.
Related Questions
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