What type of electrical current flows continuously in one direction?

The correct answer is direct current, which is characterized by the flow of electric charge in a consistent direction. This type of current is often used in batteries, solar panels, and electronic devices that require a stable voltage. In direct current systems, the electric charge flows steadily from the negative terminal to the positive terminal, making it ideal for applications that need reliable and continuous power without fluctuations.

In contrast, alternating current, which is typically used in residential and industrial power systems, periodically reverses direction. This allows for the transmission of electricity over long distances and is not suitable for devices that need a constant input.

Pulsating current refers to a current that changes in amplitude and may switch between positive and negative values but does not flow continuously in a single direction. Lastly, residual current relates to the current that flows through a protective device, usually in the context of safety devices like RCDs (Residual Current Devices), which are designed to prevent shock by cutting off power if an imbalance is detected. Understanding these distinctions is crucial for effectively working with and managing electrical systems.