Is a transformer a constant wattage device?

A transformer is not a constant wattage device because it does not convert power without loss. In practical applications, transformers can have varying efficiency based on load conditions, temperature, and the quality of the materials used in their construction.

The power rating of a transformer, measured in watts, depends on its design and operating conditions. As the load changes, the current drawn from the transformer can increase or decrease, leading to variations in the power it supplies. Additionally, losses due to resistance, heat, and magnetizing current further contribute to fluctuations in wattage.

Thus, the inability of a transformer to maintain a constant wattage across different operating conditions is a key reason why it is not classified as a constant wattage device.