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Creating electrical circuits.
Identification of elements on the electrical circuits


Reading and drawing schematics is an integral part of the industrial engineer. Standards for preparation of schematics and graphical display of elements were used extensively in the USSR and other countries. The basis here was a unified system of design documentation ESKD. In this article I want to present the basic principles and the art of drawing schematics. At the same time draw your attention that this is not a description of standards, I would like to introduce the practice, which is used in the notation of the elements and produce good quality concepts

1. Art drawing electric circuits.

Good strategy is not enough. Create a good scheme long and boring, because you always need to remember, that you create a schema for a person, not simply describes a device for a certain standard. Most schemes that have been created by ESKD, designers and engineers just ugly. So I call the drafting of concept art. Masterfully created by the scheme makes it much easier to work with the device. Therefore, I advise to redraw the scheme for a device that you serve the time

2. De facto, the principal types of industrial electrical circuits.

The first type is characteristic of the Soviet period and the companies that work the old way. Such a scheme is not suitable in all respects. The main thing to find a large plane on which it can be decomposable. After a while she'll completely useless, but take a copy of it is rather difficult. Provide clear the device for such a scheme is not possible. Surprising persistence of some large enterprises, which continue to produce such schemes. The second type of more modern and actively applied, especially in imported equipment. The disadvantage of these schemes is that the procedure simply flipping this scheme. The majority simply draw separately each element of the scheme on a separate sheet, and the connection elements show links to pages and signals. More advanced producers portrayed on separate sheets at least a chain of industrial safety equipment .

If you received a new machine, I advise you immediately draw the circuit block machine with all the elements, it will significantly reduce the time the withdrawal of equipment from his stupor. Schemes, in which respected the balance of small and large (important and not important) is very small, the manufacturer does not bother it.

3 The rules for electrical circuits.

Fig.1 Schematic diagram of the AON (Input / Output Part)
Caller ID Scheme

Here, for example, part of the scheme AON, here are the input and output signals and the way they move. The microprocessor portion of the device is not specifically shown, it is on a separate sheet. And the signals from the microprocessor of the show from the bus. Overall a tire of this circuit and microprocessor parts are connected, although it is somewhat contrary to ESKD, but once everything is clear, that where and how.

4. Graphical representation of connections.

In electrical circuits there are differences between different industries in the image of the individual elements. There are traditions in the image of the circuit elements.

Further description is based on the circuits for analog and digital devices. Plans electrical and industrial equipment, we consider separately.

4.1 Connectors.

The image interconnection lines on electric circuits

Each wire bus must have its own name. All wires in the bus with the same names are considered a single wire.

4.2 Connection with the common wires.

All signals from the same images and words are connected. Use these signs to facilitate the graphic image. Moreover, for the power wires obey the rule: "current must flow from top-down"

Images of common lines for electrical circuits

4.3 Special marking compounds.

Special designations are used to specify properties of compounds.

Image compounds on electrical circuits

5. Identification of elements on electrical circuits.

Each element of the electrical circuit is denoted by an alphanumeric code. There are many options for signs, here I quote the most common, which corresponds to GOST 2.710-81 (ST SEV 6300-88)

denote elements in electrical circuits

Usually full face value element specifies a list attached to the concept, but admits GOST 2.702-75 simplified application value element to an electrical circuit:

In some schemes, it is used for the resistors (but this is not correct)

To indicate an element type are encoded in Latin capitals

The first letter in the mandatory and defines the element type, the second letter breaks the type of items for a subset.

Author: Electron18   

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