In a step-regulator, where is the primary coil connected?

In a step-regulator, the primary coil is specifically connected across the line. This configuration allows the regulator to take the incoming voltage and adjust it to a desired level by utilizing the transformer action. By placing the primary coil across the line, it receives the input voltage directly, which it transforms into a different voltage level in the secondary coil, thereby regulating the voltage that gets delivered to the load.

Connecting the primary coil directly across the line is essential for the step-regulator's operation because it ensures that the device can properly sense the incoming voltage levels and make the necessary adjustments to maintain consistent output. This method is critical for efficiency and effectiveness in maintaining voltage stability in the electrical system.

The other potential configurations, such as grounding or connecting in series with the load, would not allow the device to function correctly as a voltage regulator, because they would either disrupt the flow of current or not enable accurate voltage adjustments.