Which of the following is an example of a non-linear load?

A non-linear load is characterized by a current that does not have a linear relationship with the voltage due to its operation, often resulting in harmonics being generated in the system. Computers are a prime example of non-linear loads because they contain switching power supplies that draw varying amounts of current over each cycle, thus leading to distorted waveforms.

In the case of light bulbs, refrigerators, and electric heaters, these devices are generally considered linear loads. Light bulbs and electric heaters typically draw a steady current that is directly proportional to the voltage, resulting in a straightforward sinusoidal current waveform. While refrigerators may exhibit some non-linear characteristics due to their compressor's operation, they primarily operate as linear loads in most scenarios. In contrast, computers, with their complex circuitry and power management systems, exemplify non-linear load behavior very clearly through the introduction of harmonics and non-sinusoidal current waveforms.