An analog computer is a type of computing device that uses continuous physical quantities to represent information. Unlike digital computers, which process data in discrete values (like 0s and 1s), analog computers manipulate variables such as voltage, current, or mechanical motion to perform calculations. They are particularly useful for simulating complex systems, such as those found in engineering and physics. These computers were widely used before the advent of digital technology and are still relevant in specific applications today. For example, differential analyzers and slide rules are classic examples of analog computing devices. While they have largely been replaced by digital computers, analog systems can still excel in real-time processing and modeling dynamic systems.