What is a transformer’s turns ratio?

• A. The ratio of input to output voltage
• B. The ratio of primary to secondary winding turns
• C. The ratio of current flowing through the windings
• D. The ratio of resistances in the circuit

Answer: (B)

A transformer's turns ratio specifically refers to the ratio of the number of turns in the primary winding to the number of turns in the secondary winding. This is a fundamental characteristic of transformers that determines how the voltages change between the primary and secondary sides according to the formula:

[ \text{Turns Ratio} = \frac{N_p}{N_s} ]

where (N_p) is the number of turns in the primary winding and (N_s) is the number of turns in the secondary winding.

This ratio is crucial because it allows for the calculation of the input and output voltages as well as the currents. The output voltage is proportional to the turns ratio when no losses are considered, indicating how effectively a transformer can step up or step down voltage levels.

In contrast, the other choices focus on different attributes of electrical circuits. The ratio of input to output voltage is related, but it depends on the turns ratio rather than being the same concept. The ratio of current flowing through the windings pertains to power transfer and efficiency, but it is not a measure of the turns themselves. The ratio of resistances within the circuit does not directly connect to the function of the transformer in terms of voltage transformation. Thus, the definition