Many modern devices are electronic. Electronic machines, such as calculators, microwave ovens, or computers, have specialized parts that control them. Each piece or specialized component of an electronic device has a particular way of controlling the passage of electricity. Each component, such as transistors, rheostats and capacitors, perform a different task and all can be combined into a circuit capable of performing complex tasks. For example, an automatic light switch has an electronic part called a light sensor that instructs the lamp to turn on when it begins to darken.
SIMPLE CIRCUITS
An electrical device works when electricity completes its passage through a circuit. This is the case of, for example, a toaster, electric razor or fan. In a simple electrical circuit, like that of a light, a manual switch completes the circuit to light the lamp.
COMPLEX CIRCUIT
In an electronic circuit, the different components control the passage of electricity. For example, a transistor opens or closes the current input, a rheostat reduces the current flow and a capacitor accumulates it. The various electronic components can be joined together in a circuit board, which can also contain one or more silicon chips.
THE MICROCHIP
A microchip contains many electronic circuits embedded in a tiny piece, or chip, of a material called silicon. The components are so small that they can only be seen with a microscope. A microchip is so small that it fits on the tip of a finger.
MATHEMATICAL MICROCHIPS
The calculators have a microchip that makes mathematical calculations at high speed. One part of the microchip remembers the numbers, and another makes the calculations.
THE COMPUTER
A computer contains many microchips. Among them, a microprocessor. The microprocessor is a special microchip with many circuits, formed by several hundred thousand components. A microprocessor allows the computer to perform millions of operations per second. The groups of operations are the programs.
