What is a circuit diagram?

A circuit diagram is fundamentally a graphical representation of an electrical circuit. This visual depiction uses symbols to denote the various components within the circuit, such as resistors, capacitors, and power sources, along with the connections between them. By illustrating the layout and relationships between different elements, circuit diagrams help in understanding the operation of the circuit and analyzing how electricity flows through it. This representation allows engineers and technicians to communicate their designs clearly and efficiently, making it a crucial tool in both education and practical applications in electronics and electrical engineering.

The other options do not encompass the essence of what a circuit diagram is. A written explanation of electrical theory refers to descriptive text that explains the principles of electricity rather than visualizing the circuitry. A measurement of voltage pertains to a specific quantity in electrical systems and does not represent circuits themselves. A type of electrical component is, instead, a part of a circuit but does not capture the concept of diagramming the entire circuit.