SU575704A1 - Thermistor - Google Patents

Description

one

The invention relates to the design of resistors, namely, thermistors, used in measurement technology as sensitive elements of thermo-anemometric converters for

measuring the flow rate of a gas or liquid.

A thermistor is known that contains a thermosensitive element made of semiconductor material with a heater mounted on it in the form of a spike. The sensing element is attached by means of leads to. TpaeepcfiMi which are fixed inside the glass bulb l.

The disadvantage of the thermistor is the 4e position of the sensing element inside a sealed glass bulb and a large inertia, which makes it impossible to use them for thermo-anemometric measurements.

Also known is a thermistor containing a semiconductor thermosensitive element with current leads placed in opposite directions located inside the ceramic tube,

on which the heating winding is wound

11 Such a thermistor

large dynamic and temperature errors, as a result of which it is not applicable in thermo-anemometric measurements.

Another thermistor is also known, which contains a semiconductor operating element and a heating winding located around it, poured with glass in the form of a bead, passing from one side to glass balls, through which the one-way current leads 2 are passed.

Said thermistor is the closest to the invention in its technical essence and the achieved result.

Claims (2)

The disadvantages of the known thermistor are significant thermal inertia, which causes large dynamic errors, large temperature deviations, the dependence of the anemometric characteristics on the thermal conductivity of the base and the depth of fixing of the thermistor in it, which makes it difficult to select the thermistors. The aim of the invention is to reduce the errors of the thermistor during hot-wire measurements. This goal is achieved by the fact that in a thermistor that contains a semiconductor operating element, a heating element and one-sided glazed current leads, the heating element is located around the glazed current leads for a portion of their length, which prevents the working element from the point of attachment of the thermistor. The drawing shows the described thermistor. The semiconductor operating element 1 is covered with a layer of glass 2, which protects it from environmental influences. Work element 1 is mounted on vitrified current leads 3 around which heating element 4 is located, made in the form of a metal spiral of high-specific-resistance wire. To protect against the influence of the surrounding environment and ensure the electrical insulation of the heating element 4 is covered with a layer of glass passing into the tail parts in the influx 5, into which the current leads 3 and the current leads 6 of the heating element helix} 1 are escaped to the outside of the electrical circuit elements; in working condition t rmorezistor strengthened so that the working elements washes gas or liquid flow rates to be measured. The working and heating elements are included in the known electrical circuits that provide the necessary modes of their operation, for example, the electrical circuits supporting the constant values of the temperatures of the working and heating elements that exceed the ambient temperature value. At the same time, the power dissipated by the working element depends on the speed of the flow washing it and does not depend on the temperature of the base in which the thermoreistor is fixed. The described design of the thermistor allows to reduce the temperature and dynamic faults: to reduce the accuracy requirements for matching the characteristics in the selective selection of paired thermo resistors and ensures that the thermistor reaches the specified operating mode at small values of the voltage applied to it, regardless of the ambient temperature. Claims A thermistor comprising a semiconductor operating element, a heating element, and one-sided vitrified current leads, characterized in that, in order to reduce errors during thermo-anemometric measurements, the heating element is decayed around the α-glazed current leads for a portion of their length separating working element from the place of attachment of the thermoregulator. Sources of information taken into account in the examination: 1.Martyushov K.I. and others. Production technology resistors, 1972, p. 268. 2. Devices and control systems, 1967. № 5. one hundred. 42-43.