Which of the following measures both voltage and current?

The correct answer is the voltmeter. A voltmeter is specifically designed to measure voltage, which is the electric potential difference between two points in a circuit. However, the original question pertains to measuring both voltage and current, which isn’t feasible with a standard voltmeter alone.

While voltmeters are essential for measuring voltage, to measure both current and voltage in an electrical circuit, specialized devices called multimeters are typically used. A multimeter can function as both a voltmeter (for measuring voltage) and as an ammeter (for measuring current).

The other choices, such as the ammeter, are used solely for measuring current, while transformers and capacitors serve distinct purposes in electricity, such as changing voltage levels or storing electric charge, respectively. Understanding the function of these devices is key to comprehending basic electrical principles in beauty therapy practices involving equipment that utilizes electrical components.