Criteria for the selection of soybeans and oy

When choosing SOI and OU, it should be borne in mind that the amount of information should be necessary, since an increase in volume leads to a decrease in reliability. The main technical and economic indicators of SDI:

functional - functionality, size of characters, brightness, multicolor, contrast, viewing angle;

electrical - power consumption ***, compatibility with IC, complexity of autonomous power supply and control circuits;

constructive - - resistance to external influences, indicators. reliability, constructive design and ease of fixing.

All op-amps consist of a switching or adjustment unit and a drive unit that transmits the operator's efforts. By type of drive device, the OS is divided into buttons (keys), toggle switches, rotary switches and knobs. There are: functional indicators of the OS — the nature of the control movements and the degree of their compliance with the stereotypes of movement, control efforts; electrical — number of switching circuits, currents, frequency range; constructive — ease of installation, overall dimensions, design of the drive unit and its aesthetic appearance.

In all cases, when choosing SOI and OS, their cost, compliance with the principles of the construction of a radio electronic device (analog or digital) and prospects should be taken into account.

Signs Synthesizing Indicators. In matrix indicators with symbolic synthesis, any valid symbol is formed from a permanent set of elements (segments) displayed in various combinations. This method of constructing numbers or letters of the alphabet is well combined with discrete combinatorial control, which is easily implemented in digital electronic circuits. Since the complexity of the PIO and control devices depends on the number of segments, it is natural to strive to reduce them, the seven-segment indicators, even for the image of numbers, give character patterns that are significantly different from the standard type characters. Seventeen-segment indicator allows you to play numbers, letters of the Latin and Russian alphabets.

According to the physical principle of operation, SDIs with the characterization are divided into electroluminescent, vacuum luminescent, light-emitting diode and liquid-crystal.

Electroluminescent indicators have a flat design, giving a large viewing angle, high mechanical strength, low cost. They are multicolored, which provides additional color coding of information. Main disadvantages: low brightness and its decrease several times during the first thousand hours of operation; the need for special power supply and control circuits that are not consistent with the power supply circuits of the IC.

Vacuum fluorescent indicators have high brightness, the possibility of obtaining symbols of several colors on one indicator, low power consumption ***, the ability to switch using conventional digital IC, but low mechanical strength.

LED indicators have high mechanical strength, working voltage compatible with IC, long service life. The main disadvantage is the small size of the luminous surfaces.

In liquid crystal indicators, high contrast values ​​(up to 100: 1) are obtained in bright light, for example, in the open air. The indicators have a flat design, the power consumption is low, the low power, low cost, compatible with the IC. Disadvantages: limited temperature range, fallen speed, the need for illumination at low levels of illumination.

All types of indicators are produced in both single-digit and multi-digit versions, which simplifies their mounting on the front panel, improves the appearance of the device.

The cathode ray tubes (CRTs) allow imaging of information in the form of visual models that are most quickly identified by the operator — for example, the situation on the radar indicator, signal waveforms, and so on. When designing a radio electronic system, it should be taken into account that CRTs are usually the most complex and dimensional Products that require additional insertion of significant nodes in the volume and mass, for example, high-voltage, electromagnetic shielding of a tube, etc.

Flat matrix screens are in fact 1-synthesis indicators with dotted segments. Gas-discharge display panels of alternating current contain a sufficiently large number of elements (1024x1024), have a different resolution (5 ... 10 elements per centimeter), there may be red, yellow, green and blue colors of the flow. Despite relatively small dimensions, flat matrix indicators are quite complex (products, such as the IVLG1-128 / 128 indicator with a matrix of 128 x 128 dots with an information field size of 127 x 127 mm, have 579 outputs. Currently, electroluminescent vacuum matrixes and vacuumless screens.

Light-emitting elements and light boards. For filing warning or alarm signals, indication of two-three states of the RES use LEDs, compact instrument lamps and signaling gas lights. Instrument lamps and gas lamps are unreliable elements (service life from 10 to 1000 hours). Therefore, they must be placed in easily accessible places, installed in easily detachable holders — cartridges, which are covered with translucent caps of different colors. Light boards are used in cases when it is necessary to inform the operator of additional textual information, for example, instructions for an action, or to indicate a relatively large number of states. The light panel consists of fittings, fasteners, banners with inscriptions of illuminating bulbs. When developing the design of the scoreboard, it is necessary to provide for the possibility of quick replacement of light bulbs. It is much more convenient to use commercially available boards, which in fact represent the sign-synthesizing indicators with segments of a special form.