What is a scanner

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For those who have questions about computer peripherals, this article will be useful, in particular we will describe what a scanner is.

A scanner is a device that turns light pulses into a stream of logical zeros and ones. With its help, you can transfer any document or photo on paper to a computer and watch it already through the monitor. In other words, it turns analog data into digital information, transferring it from paper, film and others into a text or graphic file.

The basic element of a scanner is a CCD (Charge Coupled Device), which turns light energy into electrical energy (or CIS matrix) or a PMT (Photo Multiplier Tube). Photo Multiplier Tubes are used only in complex and expensive professional drum scanners. Let's consider the principle of operation of a scanner with CCD-matrix.

The matrix is a set of semiconductor devices (diodes), which become sensitive to light if an external voltage is applied to them. The object is illuminated by a xenon lamp. The rays reflected by the object are projected onto a CCD matrix using a system of mirrors and lenses.

Under the influence of light and applied external voltage, the matrix generates an analog signal, which changes with the movement of the scanner and the intensity of reflection of different fragments of the object.