2. Tutorial: Mechanic - electrician Topic: Electric measurement the 2nd. year Measuring of non - electrical quantities 2 – sensors Prepared by: Ing. Jiří Smílek Projekt Anglicky v odborných předmětech, CZ.1.07/1.3.09/04.0002 je spolufinancován Evropským sociálním fondem a státním rozpočtem České republiky.

3.  Distribution of sensors according to the used physical phenomenon or principle of scanning: mechanical quantities - position, track, speed, revolutions, force, torque, thermal variables - temperature, heat flux, heat radiological variables - intensity of visible, infrared and ultraviolet radiation quantity of hydraulic systems - pressure, flow, revolutions, noise biological variables - blood pressure, pulse, temperature.. nuclear variables - type of radiation α, β, γ

4.  Measurement of movement in the room: Motion sensor (pyroelectric sensor) The measured physical quantity: - an infrared beam Application: - capture the movement of people in rooms, in buildings or triggers an alarm. Functions - pyroelectric sensor responds to the thermal radiation emitted by the human body. To increase the sensitivity of the sensor it is placed in the focus of a parabolic reflector, or converging lens. The sensor signal is amplified, evaluates and responds to human movement, the sensor sends a signal. The actuator adopts an activation signal and switches for example for a certain period lighting or triggering an alarm.

5.  Measurement of thermal quantities: Functions - in the weld two metal conductors with different concentrations of free electrons resulting from the change in temperature (the temperature of loose ends), for example when heated, the power supply, that can be measured between the free ends of conductors. Thermocouple The measured physical quantity - the temperature T (° C), Applications: - measure surface temperature of solids,

6.  Measurement of thermal quantities: Properties: A pair of metal (alloy): Fe (+) – CuNi (-) is used for temperature measurement – 200°C to 700 °C, NiCr (+), Ni (-) for 200°C to 1200 °C, NiCrSI (+) – NiSi (-) to 1300 °C PtRh (+), Pt (-) to 1600 °C Thermocouple The measured physical quantity - the temperature T (° C) Application: - measurement of the surface temperature of solids,

7.  Measurement of thermal quantities: Functions - A thermistor is a semiconductor component that is used as a temperature-sensitive component. Types : NTC and PTC thermistor. NTC is a thermistor with negative temperature coefficient, which means that heating resistance components decreases resistance The PTC thermistor resistance increases with heating Thermistor: The measured physical quantity - the temperature T (° C) Application: - measurement of temperature of oil, water, indirect measurement of liquid flow rate, liquid level indicator - monitoring overflow tank with heating oil, thermometer for microwave ovens....

8.  Measurement of thermal quantities: Resistive thermal sensor: The measured physical quantity - the temperature T (° C) Functions : - They use the principle of change in resistance when the temperature changes, based on the formula: R 2 - resistance at higher temperature (Ω) R 0 - resistance at reference temperature (Ω) Δϑ - temperature difference (°C) α - temperature coefficient of resistance (in tables) (K -1 ) for aluminum Al is = 0,004 K -1 ; for copper Cu is = 0,0042 K -1

9.  Name the distribution of sensors by sensing the type of variable ◦ mechanical quantities - ◦ thermal quantities - ◦ radiation quantities - ◦ quantities of hydraulic systems - ◦ biological quantities -  Describe the use of piezoelectric sensors – Fill in the missing words ◦ Application: - capture the …………….people in ……………., in buildings or ………….alarm.  Describe the use of a thermocouple Fill in the missing words ◦ Application : - …………..surface …………….. of solids, ◦  Explain the difference between an NTC and PTC thermistor Fill in the missing words  NTC is a thermistor with negative …………………… ………………………, which means, that ………………… resistance components.........................................  The PTC thermistor............................. with heating ◦

10.  Name the quantities on which depends the resistance change with temperature fill in the missing words:  R 2 -...........at higher...........(Ω)  R 0 - resistance at........... temperature (Ω)  Δϑ -......................(°C)  α -.......................... resistance (in...........) (K -1 )

11.  Mužík, J. Management ve vzdělávání dospělých. Praha: EUROLEX BOHEMIA, 2000. ISBN 80-7361-269-7.  Operační program Vzdělávání pro konkurenceschopnost, ESF 2007 – 2013.  Dostupné na: http://www.msmt.cz/eu/provadeci-dokument-k-op-vzdelavani-pro- konkurenceschopnosthttp://www.msmt.cz/eu/provadeci-dokument-k-op-vzdelavani-pro- konkurenceschopnost  Učebnice Elektrická měření – Ing. Pavel Vylegala, SŠE Ostrava, 2006  Učebnice Elektrické měření – SNTL, 1981  Základy Systémové techniky budov - Ing. Jan Vanuš,