Photodiode

In electronics and radio engineering, graphical symbols play, perhaps, the greatest role. In order, for example, to understand the device of a crane or machine, you only need to have their assembly drawings with a sufficient number of sections and drawings of individual parts. electrical drawings.However, from these drawings it is impossible to get an idea of ​​the principle of operation of the devices, diagrams are required here.

Electrical circuits - they are exactly what you need to understand the principle of operation of any electrical or electronic device. All radio components and electrical connections on the wiring diagrams are indicated conditionally.

The elements in the diagrams are shown schematically :-).

But this convention did not appear immediately. At the beginning of the development of radio engineering, they simply copied this or that radio apparatus from nature. We sketched out all its details and connections between them. As the complexity of radio devices grew, this method became more and more problematic. Over time, minor details began to be omitted, leaving only the main essence, simplifying individual details.

For example, a capacitor consisting of two plates isolated from each other was denoted by two parallel lines.

There were more and more devices and, accordingly, schemes too. Radio equipment began to be produced at factories and in various fitmas. On wiring diagrams made in different places of the same country, the designation of the same element might not be the same.

What can we say about international trade.

In order for specialists of any country to be able to correctly and unambiguously read the electrical circuit, a unified system of conventional graphic symbols is needed. This is the responsibility of the International Electrotechnical Commission (IEC).

Such a system has been created.

The switch stator is a ring made of insulating material, on which spring contacts are attached around the circumference.

Inside the ring there is a rotating disc made of insulating material, on which the conducting sectors are fixed.

Stator contact springs, except for one, do not reach the rotor, and one - the elongated spring - is in constant contact with the rotor sectors.

The rotor sectors each have one elongated protrusion making contact with one of the short stator springs.

When the rotor turns, the contacts are switched.

Such switches are characterized by the number of positions and directions, that is, the number of independent switched circuits.

Depending on the number of biscuits and moving contacts, the switch can have a different number of positions and directions.