In the context of alternating voltages and currents, which device typically uses direct current (DC) to operate?

• A. A battery-powered flashlight
• B. An induction motor connected directly to mains power
• C. A transformer used in an AC power supply
• D. A household incandescent lamp plugged into a wall outlet

Answer: (A)

Verified step by step guidance

1. Understand the difference between alternating current (AC) and direct current (DC). AC periodically reverses direction, while DC flows in one constant direction.
2. Identify the devices listed and consider their typical power sources: a battery-powered flashlight uses batteries (which provide DC), an induction motor connected to mains uses AC, a transformer operates with AC to change voltage levels, and a household incandescent lamp plugged into a wall outlet uses AC.
3. Recall that batteries supply direct current (DC), so any device powered by batteries typically operates on DC.
4. Recognize that devices connected directly to mains power (like the induction motor and household lamp) use alternating current (AC) because mains electricity is AC.
5. Conclude that the device that typically uses direct current (DC) to operate is the battery-powered flashlight.