An analog circuit is a type of electronic circuit that processes continuous signals. Unlike digital circuits, which work with discrete values (like 0s and 1s), analog circuits can represent a range of values. This allows them to handle real-world signals such as sound, light, and temperature, making them essential in devices like radios and amplifiers. These circuits use components like resistors, capacitors, and transistors to manipulate electrical signals. For example, an amplifier increases the strength of a weak signal, while a filter can remove unwanted frequencies. Overall, analog circuits are fundamental in various applications, from audio equipment to sensor systems.