Analog computer

Some machines solve problems using physical parts.

They do not use code like a phone. Instead, they use things like gears or wires.

A clock is a good example. Moving gears turn the hands to show time. These machines can also use water or electricity.

They were very fast for their time. People used them to help fly planes. They are very clever tools.

An analog computer is a special kind of machine. It does not use digital code like a phone. Instead, it uses physical things to solve problems. These things can be moving gears, electricity, or even water.

Think about a mechanical watch. The gears turn to move the hands. This is a way to show time. Analog computers work in a similar way. They use a model to represent a problem.

Some analog tools are very simple. A slide rule helps people with math. It is used to multiply and divide.

Other tools are very complex. Long ago, people used the Antikythera mechanism to track stars.

In the past, these machines were very fast. They helped pilots fly planes. They were also used to predict tides with water.

Some machines used many tubes and wires to work. Even today, they are used to teach how systems work.

An analog computer is a special kind of machine used to solve problems. Most people think of computers as digital devices that use code. However, analog computers work in a very different way. They use physical things to represent math. These things might be moving gears, electrical signals, or even flowing water.

Instead of using a list of instructions called an algorithm, they use a physical model. This model is called an analogon. The machine's structure is built to look like the problem it is solving. This allows it to model real-world systems very closely.

How these machines work depends on what they are made of. A simple analog tool is a slide rule. It is a hand-operated device used for multiplication and division.

A mechanical watch is another great example. In a watch, interlinked gears rotate to move the hands. This continuous movement represents the passing of time. More complex machines might use electricity or hydraulics. For example, a hydraulic computer uses water to represent a system. One machine called the MONIAC was a hydraulic model of a national economy.

It used water to show how money moves through a country.

People have been building these machines for a very long time. One of the oldest is the Antikythera mechanism. It was found in a shipwreck near a Greek island.

This device was used to track the positions of stars and planets. In the 1600s, people began using slide rules for math. Later, in 1872, Sir William Thomson made a tide-predicting machine. It used wires and pulleys to calculate the tides for ships.

In the 1920s, Vannevar Bush helped develop mechanical differential analyzers. These machines used wheels and discs to solve difficult math equations.

Many important machines were built during the 1900s. During World War II, analog computers were used for many tasks. Some helped pilots aim bombs or guide rockets. For instance, Helmut Hölzer built an electronic computer in 1942. It helped guide the V-2 rocket by measuring its movement.

In 1947, the scientist Enrico Fermi invented the FERMIAC. He used it to study how neutrons move. Other large machines, like network analyzers, were built to study electricity. By the end of the 1950s, over 50 of these large analyzers existed.

You can see the link between these machines and your own life. Even though digital computers are now much more common, analog ideas remain. Some aircraft still use flight computers that use analog parts.

These machines were often much faster than early digital computers. Today, they are still used in flight simulators to teach pilots. They are also used in universities to teach how control systems work.

They remind us that math can be seen in the physical world.

An analog computer is a specialized machine used to model mathematical problems through physical phenomena. Unlike digital computers, which use discrete values and symbols to represent data, analog computers use continuous signals. These signals can be electrical, mechanical, or hydraulic quantities. These physical properties behave according to specific mathematical principles to solve a problem. This method is known as analog computation.

Instead of following a list of step-by-step instructions called an algorithm, these machines use a physical structure called an analogon. This structure is a model that is analogous to the system being solved. This allows the machine to represent the problem directly through its own physical movement or state.

The mechanism of an analog computer depends on the medium it uses to represent data. In a mechanical analog computer, moving parts like gears or linkages represent variables. For example, the rotation of interlinked gears in a mechanical watch continuously drives the hands to represent time. In hydraulic analog computers, the flow or pressure of liquid represents mathematical values. One famous example is the MONIAC, which used water to model a national economy.

Electrical analog computers use voltages or currents to represent information. These machines can be quite complex. One example is Project Typhoon, which used over 4,000 electron tubes and 6,000 plug-in connectors to allow for programming. Each physical change in the medium, such as a gear turning or a voltage rising, corresponds to a specific mathematical change in the model.

Analog computers vary greatly in their complexity and design. The simplest forms are tools like the slide rule. Invented around 1620–1630, the slide rule is a hand-operated device used for multiplication and division. It uses sliding scales to perform calculations.

More advanced versions included added scales for square roots, cubes, and trigonometry. Other types include the planimeter, which is a manual instrument. It calculates the area of a closed figure by tracing over it with a mechanical linkage. There are also hybrid computers, which combine digital and analog components. These systems can use analog parts to calculate speed or altitude and then send that data to a digital PC.

The history of analog computation stretches back to antiquity. One of the earliest known examples is the Antikythera mechanism. This device was discovered in a shipwreck near the Greek island of Antikythera. It dates to between 200 BC and 80 BC during the Hellenistic period.

Historians describe it as an early mechanical analog computer used to determine the positions of heavenly bodies. In the 16th century, the sector was developed to solve problems in trigonometry and navigation. Later, in 1872, Sir William Thomson invented a tide-predicting machine. This device used a system of pulleys and wires to automatically calculate predicted tide levels for navigation.

During the 20th century, analog computers reached high levels of sophistication for scientific and military use. In the 1920s, Vannevar Bush helped develop mechanical differential analyzers. These machines used wheel-and-disc mechanisms to solve differential equations through integration. In 1942, Helmut Hölzer built a fully electronic analog computer at the Peenemünde Army Research Center. This device served as an embedded control system to calculate V-2 rocket trajectories. It used measurements from gyroscopes to stabilize and guide the missile.

Other scientists used them for specific research, such as Enrico Fermi, who invented the FERMIAC in 1947 to study neutron transport.

These machines were highly significant due to their speed in specific applications. Even after digital computers were invented, analog computers were often much faster for certain tasks. This kept them in use for many decades. For instance, large network analyzers were built to solve electrical power problems that were too large for manual calculation. By the end of the 1950s, more than 50 of these large analyzers had been constructed. They were essential for studying nuclear physics and designing complex structures. In the Netherlands, analog computers like the Deltar were used to support the Delta Works project by predicting tidal currents.

Today, analog computing remains relevant in specialized fields. While they became largely obsolete for general computing in the 1960s, they are still used in flight simulators. They are also used in aircraft flight computers.

Some modern hybrid systems use analog components to model the flight of VTOL aircraft, such as the Harrier jump jet. They are also used in universities to teach the principles of control systems. This shows how the concept of using physical models to understand the world continues to connect mathematics to reality.