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1) What is a hot-wire anemometer and what is it used for? What is a thermal tran

ID: 1622642 • Letter: 1

Question

1) What is a hot-wire anemometer and what is it used for? What is a thermal transport mass flowmeter used for and how is it made? What is an ultrasonic flowmeter?

2) Explain the different types of RTD’s and what the advantages of each are.

3) How can you use a capacitor as a (1) microphone, as a (2) level sensor, as a (3) proximity

sensor?

4) What is an Eddy current displacement sensor? Draw a diagram for such a sensor and explain

how it works. What is the typical range and resolution of such a sensor?

5) How would you design a measurement system using an LVDT (from signal to ADC).

Explain why we use a phase sensitive demodulator in such a measurement system.

6) What is the main problem that can occur from unsuitable grounding? Explain with means of

a graph.

7) The DAQ that you used in your lab includes both an instrumentation amplifier and an A/D

converter. Explain what the instrumentation amplifier is and draw its circuit. Why not just used an inverting amplifier? Why not just use a non-inverting amplifier. What are the different issues you want to consider if you want to connect a sensor to this DAQ?

8) Consider the following types of position sensors: inductive, capacitive, eddy current, ultrasonic. For the following conditions, indicate which of these types are not suitable and explain why:

Environment with variable humidity,

Target object made of aluminum,

Target object made of steel,

Target object made of plastic,

Target object several feet away from sensor location

Environment with significant temperature fluctuations

Explanation / Answer

1) The Hot-Wire Anemometer is the most well known thermal anemometer, and measures a fluid velocity by noting the heat convected away by the fluid.

An anemometer is a device used for measuring the speed of wind.

A thermal mass flow meter is a precision instrument that measures gas mass flow

Ultrasonic flowmeters use sound waves to determine the velocity of a fluid flowing in a pipe.