Section 1: Sensors and Measuring Systems

What is the primary function of a sensor in a mechatronic system?

To detect a measurand and transform it into a suitable signal

Which of the following is NOT a classification of measuring quantities mentioned in the sources?

Biological quantities

In the context of sensor properties, what is the "main effect"?

The phenomenon responsible for generating the desired measuring signal

A sensor's static behavior defines its sensitivity. How is sensitivity described?

The ratio of the change of the electrical output signal to the change of the measured variable

What is "dead space" in sensor properties?

The range of different input values over which there is no change in output value

Which of these is an advantage of using an analogue interface for signal transmission?

It is easy to implement and very common.

A potentiometer is an example of what type of sensing element?

Resistive

How does the resistance of a photoresistor change with increasing incident light intensity?

It decreases.

What is the primary advantage of photointerrupters over mechanical switches?

They are non-contact (optical) switches, improving reliability by preventing wear and tear.

In an optical encoder, what is the purpose of the "mask"?

To have corresponding tracks with small perforations (windows) that are covered or open as the disk moves.

What is a key drawback of an incremental encoder

It cannot determine the absolute position of the shaft at power-up without rotating it until an index pulse is received.

Why is Gray code preferred over straightforward binary encoding in absolute encoders?

It ensures only one bit value changes as the shaft moves from one position to the next, avoiding ambiguous outputs.

Which sensor type is typically measured indirectly by using it to control the frequency of an oscillator or vary the level of coupling of an AC signal?

Capacitance sensor

What is the working principle of a Linear Variable Differential Transformer (LVDT)?

Detection of displacement by comparing the magnitude and phase of an AC signal from a pickup coil to an excitation coil.

What phenomenon is the Hall effect based on?

The production of a voltage difference across an electrical conductor, transverse to an electric current and an applied magnetic field.

Consumer goods and low-cost appliances generally require high-precision measurement and a modular arrangement of the measuring system.

False

Side effects in sensors are beneficial signals that enhance the desired measuring signal.

False

The reliability of a sensor is described by characteristic parameters such as "mean time between failures" (MTBF).

True

Digital signals must be converted to analog prior to transmission through an analogue interface.

True

A flexible bend sensor changes resistance as the material bends and stretches due to conductive ink between electrical contacts.

True

Reflector-type photosensors position light receiving and emitting elements on opposite surfaces to detect objects.

False

In 4X resolution decoding for optical encoders, a count is generated for each rising and falling edge of both pulse trains, resulting in four times the angular resolution.

True

A mercury switch can be used to provide precise, continuous measurement of tilt angle.

False

Capacitive proximity sensors can only detect metallic targets.

False

Laser interferometers are capable of measuringincremental linear motions with resolution on the order of millimeters.

False