Explore topic-wise InterviewSolutions in .

Right choice is (a) Effective no of bits

Easy explanation: The dynamic range of an ADC is OFTEN summarized in terms ofits effective no of bits(ENOB), the number of bits of each measure it RETURNS that are on average not noise. An ideal ADC has an ENOB EQUAL to its RESOLUTION.

Correct ANSWER is (b) Infrared

To elaborate: Infrared touch SCREEN technology does not incorporate an overlay. Instead, a FRAME surrounding the display CONSISTS of LEDs on one side and PHOTOTRANSISTOR detector on the other.

The correct option is (d) 10 WAYS

Best explanation: The most common ways for IMPLEMENTING ADC are direct conversion, successive approximation, RAMP compare, Wilkinson, integrating, delta encoded, pipelined, sigma delta, time interleaved, intermediate FM stage, other TYPES.

Right choice is (d) SURFACE Acoustic Wave

For explanation I would say: SAW touch SCREEN technology is based upon TWO transducers and a reflector placed on the GLASS surface. The wave is dispersed ACROSS the screen by bouncing off the reflector arrangement and received by the transducers.

The CORRECT CHOICE is (a) 2 TYPES

Easiest explanation: There are two types of sensors: capacitive sensor

Resistive sensor.

The CORRECT ANSWER is (b) Bits

To explain: The VALUES are usually stored electronically in binary form, so the resolution is usually EXPRESSED in bits.

Right option is (B) Continuous, time

Easiest EXPLANATION: The analog signal is continuous in time and it is NECESSARY to convert this to a flow of DIGITAL values.

Correct answer is (a) True

The best I can explain: The conversion INVOLVES quantization of the input, is it necessarily introduces a SMALL amount of error. Furthermore, INSTEAD of continuously performing the conversion, an ADC does the conversion periodically, sampling the input.

Right CHOICE is (b) 2 types

For explanation I would say: There are TWO types of capacitive touch sensors

1. surface capacitive SENSING

2. Projected capacitive sensing

In surface capacitive sensing, an insulator is applied with a conductive coating on one side of its surface.

In projected capacitive sensing, the whole surface is not changed, but an X-Y GRID conductive material is placed between two insulating MATERIALS.

Correct option is (a) Flash ADC

The best explanation: A direct conversion ADC or flash ADC has a BANK of comparators SAMPLING the input signal in parallel, each firing for their DECODED VOLTAGE range.

The correct option is (b) Capacitive touchscreen

For EXPLANATION: Commonly utilized for industrial purpose, capacitive touch SCREEN consists of a GLASS overlay, COATED with a conductive material such as Indium Tin Oxide.

Correct option is (d) SUCCESSIVE approximation

To explain: A successive approximation ADC uses a comparator to successively NARROW a range that contains the INPUT voltage.

Correct choice is (C) APR

Easiest explanation: An APR TOUCH screen is made up a GLASS overlay and FOUR transducers attached to the back exterior. When the screen is touched, the friction CREATES acoustic waves.

Right CHOICE is (C) twice the highest FREQUENCY

The best I can explain: Nyqist RATE, defined as twice the highest frequency of interest, then all frequencies in the signal can be reconstructed.

Right answer is (a) Analog device

Easy EXPLANATION: An input CIRCUIT called a SAMPLE and hold performs task, most cases by USING a capacitor to store the analog voltage at the input, and using an electronic switch or gate to DISCONNECT the capacitor from the input.

The correct answer is (c) Phase NOISE

The best I can explain: CLOCK JITTER is caused by phase noise. Phase noise is the frequency domain representation of rapid, short term, RANDOM FLUCTUATIONS in the phase of a waveform, caused by time domain instabilities.

The correct option is (d) Volts

The EXPLANATION is: Resolution can also be defined electrically, and expressed in volts. The minimum change in voltage required to guarantee a change in the OUTPUT code LEVEL is called least SIGNIFICANT BIT.

Right choice is (d) Optical Imaging

To ELABORATE: This TOUCH screen technology is popular for its VERSATILITY and SCALABILITY. Optical imaging relies on infrared lights.

The correct answer is (b) 3 types

The explanation is: There are THREE types of resistive TOUCH sensors: 4-wire, 5-wire, 8-wire.

4-wire resistive touch SENSOR is most cost EFFECTIVE. 5-wire resistive touch sensors are most DURABLE. 8-wire resistive touch sensor, each edge of the sensor provides a sensing line.

The correct answer is (a) Resistive touchscreen

The best EXPLANATION: The inside surface is coated with a transparent material that makes ELECTRICAL contact when pressure is applied. Whilst resistive SCREENS are durable and easy to integrate, they can only offer 75% clarity.

The correct choice is (d) Resistive touchscreen

The explanation: The INSIDE SURFACE is coated with a transparent material that makes electrical CONTACT when PRESSURE is applied. Whilst resistive SCREENS are durable and easy to integrate, they can only offer 75% clarity.

Right option is (d) Anti-ALIASING filter

To explain: To AVOID aliasing, the input to an ADC must be low pass filtered to remove FREQUENCIES above HALF the sampling rate. This filter is called an anti-aliasing filter.

Correct ANSWER is (a) Capacitive TOUCH sensor

Best explanation: Capacitive touch sensors are widely USED in most of the portable devices like mobile phones and MP3 PLAYERS. The reason for this development is durability, robustness, attractive product design and cost.

The correct choice is (a) I2C

To EXPLAIN I would say: Microcontroller COMMUNICATION is via standard I2C, where the HOST can set measurement parameters and request results. If desired, programmable threshold allow the VCNL4100 to INTERRUPT the host once threshold values are crossed, thereby minimizing device polling.

Correct option is (a) Proximity sensor

Best EXPLANATION: A proximity sensor is a sensor able to detect the presence of nearby objects WITHOUT any physical contact. A proximity sensor OFTEN emits an ELECTROMAGNETIC field or a beam of electromagnetic radiation, and looks for a change in the return signal.

Correct option is (b) DIFFERENTIAL Pressure MEASUREMENT

The best explanation: In differential pressure measurement, pressure of two distinct positions are COMPARED. For example, pressure difference calculated by measuring it at different floors of a tall building will GIVE us differential pressure.

The correct OPTION is (b) To protect hard drives from damage

The best EXPLANATION: Accelerometer in laptops protect hard drives from damage. If the laptop were to SUDDENLY DROP while in use, the accelerometer would detect the sudden free fall and immediately turn off the hard drive to avoid hitting the READING heads into the hard drive platter.

The correct answer is (d) Ultrasonic Proximity Sensor

To explain: They are WIDELY USED in AUTOMOTIVE such as PARKING sensors. Ultrasonic Proximity Sensors are used in automotive.

The CORRECT choice is (c) Temperature sensor

The EXPLANATION: Electric motor protection has a temperature sensor in it to verify the temperature which is EXCEEDING its LIMITS or not.

The CORRECT choice is (b) Gauge pressure SENSOR

For explanation I WOULD say: This sensor measures the pressure RELATIVE to atmospheric pressure. A TIRE pressure gauge is an example of gauge pressure measurement; when it indicates zero, then the pressure it is measuring is the same as the ambient pressure.

Right choice is (b) RESISTANCE Thermometer

For EXPLANATION I WOULD say: An RTD, measures temperature by correlating the resistance of the RTD with temperature. An RTD consists of a film or, for greater accuracy, a wire WRAPPED around a CERAMIC or glass core.

Right answer is (a) Accurate results

Easiest explanation: Monnit wireless temperature sensor use a THERMISTOR to accurately measure temperature. These sensors are PERFECT for monitoring ambient TEMPERATURES around the sensors physical location.

The CORRECT choice is (a) True

Explanation: A RETAILER can use a customer’s proximity to a product to SEND deals and coupons directly to their SMART phone.

Right CHOICE is (C) Thermal Conductivity

Explanation: These sensors are suitable for use in environments that have HIGH temperatures. They measure humidity by CALIBRATING the difference between the thermal conductivity of DRY air and that of moist air.

Right answer is (C) +/- 0.35% FS

Easiest EXPLANATION: ONE of the main feature of pressure SENSOR is its stability which is +/-0.35% FS(Full SCALE).

The correct option is (b) 2 types depending on measurement UNITS

Explanation: According to the measurement units, humidity sensors are divided into TWO types: Relative Humidity(RH), and Absolute Humidity(moisture) sensors. Most humidity sensors are relative humidity sensors and use DIFFERENT sensing PRINCIPLES.

Correct option is (a) Inductive Proximity SENSOR

For explanation I would say: CAPACITIVE Proximity Sensor indicates level and the fill AMOUNT present in CONTAINERS, behind covering. They are used to track all objects including non-metallic ones.

Correct choice is (c) Dryness of gas

The best EXPLANATION: DEW POINT and FOST point are often used when the dryness of the gas is important. Dew point is also used as an indicator of water vapor in high TEMPERATURE processes, such as industrial drying.

Correct option is (a) True

The explanation is: Displacement and ACCELERATION are related by fundamental SCALING law. A HIGHER resonant frequency implies less displacement or low sensitivity.

Right answer is (a) Pressure sensor

Easy explanation: BAROMETERS and pressure gauges are the most POPULAR sensors used for IOT ECOSYSTEM. Barometers are an absolute help in weather FORECASTING as in accurately measures the AMBIENT air.