What characterizes a "secondary circuit"?

A secondary circuit is defined by its position in relation to a transformer, specifically involving the low voltage side. Transformers work by converting electrical energy from one voltage level to another, and the secondary circuit is where the output occurs after the voltage has been reduced from the primary circuit. This low voltage side is crucial for delivering power to end-use devices safely and efficiently.

The other options do not accurately describe a secondary circuit. The primary circuit generally operates at higher voltage, whereas the secondary circuit operates at lower voltage following transformation. While secondary circuits can be part of systems incorporating generators, it is not their defining characteristic. High-frequency signaling, which may apply to certain applications, is not typical of the general function of a secondary circuit.