To boost the voltage by 5%, how should the secondary coils of a transformer be connected?

To boost the voltage by 5% using a transformer, connecting the secondary coils in parallel is the correct approach. When secondary coils are connected in parallel, they allow for a slight increase in voltage by sharing the load while maintaining the nominal voltage of individual coils. The output voltage can be adjusted slightly based on how the coils are configured and the load connected to them.

In this specific scenario, using parallel connection allows multiple coils to work simultaneously to slightly increase the overall output voltage. This can be effective in situations where a small voltage boost is needed without significantly altering the total capacity of the system.

On the other hand, connecting the coils in series generally increases voltage significantly rather than just a small percentage. Connecting in a loop or in reverse does not apply to typical transformer operations for boosting voltage in a straightforward manner.