Electro MECH HW

• Write the geometry type that each picture represents (full name, not just the acronym : DIP Dual In Line

  
• Write the geometry type that each picture represents (full name, not just the acronym) : SMD Surface Mount Device

  
• What does ROM stand for? And what is its application?

  Read only memory. Typically, it is used to store permanent software in devices, programed by a manufacturer.
• What does EEPROM stand for? And what is its application?

  Electrically erasable programmable read only memory. It is used in most programmable devices, from microcontrollers to computers. For example it is found in the Arduino UNO microcontroller.
• What does it mean when a memory is termed volatile? What type of memory is volatile?

  Volatile memory is such that, once power is off, all data is deleted. RAM (Random access memory) is volatile.
• In simple terms, what does an analog to digital converter do with the signal? (1-2 line answer)

  • Analog signals are continuous and digital signals are discrete (“pixelated”), so an analog to digital converter must discretize the signal.
• What does PWM stand for? And what can a PWM output do that others usually cannot?

  Pulse width modulation. PWM pins output an oscillating signal such that the “perceived” output is mid- range, instead of just ON or OFF.
• If an output pin has resolution of 7-bits, what is the range of the raw output value?

  7-bits → 27 = 128
• • A sensor’s sensitivity is determined by (FE Exam)
  • the ratio of output signal to input signal
• What is the difference between a transducer and a sensor? (FE Exam)

  A sensor is a transducer, but not every transducer is a sensor. Transducers are devices that change other types of energy into electrical energy and vice versa, sensors only change other types of energy into electric energy, not vice versa.
• Consider the resistor equation 𝑅 = 𝜌𝐿, where 𝜌 is the material resistivity, 𝐿 is the resistor length and 𝐴 is its cross sectional area.In a potentiometer, which one of these factors is altered?

  • 𝐿, length.
• Consider the resistor equation 𝑅 = 𝜌𝐿, where 𝜌 is the material resistivity, 𝐿 is the resistor length and 𝐴 is its cross-sectional area. What kind of measurand can a potentiometer measure?  Angle, sometimes torque as well.
• What type of sensor responds to a change in pressure/force? (FE Exam)

  Piezoelectric sensors.
• What are the similarities and differences between a photodiode and a phototransistor?

  Both devices detect intensity of light by outputting an voltage difference, however a phototransistor requires power to work, while a photodiode does not. Phototransistors are also considered more sensitive on average.
• What is the measurand in an optical position sensor that uses laser interferometer?

  The measurand is the difference in phase of light between the emitted beam and the reflected beam.
• What is the measurand in an optical speed sensor?

  Frequency difference of light.
• A submarine sonar (ultrasonic sensor) emits a pulse signal for 5ms and detects a response 6s after emission began. How far is the detected object? Consider that sound travels at 1500 m/s underwater.

  • 𝑣 = 𝑑 → 𝑑 = 𝑣 ∙ 𝑡 → 𝑑 = 1500𝑚/𝑠 ∙ 6𝑠 = 9000𝑚/2=4500m
• Thermistor Activity

  
• LED activity

  
• Create a circuit to turn on an LED using pin 3 as OUTPUT. Remember that most inputs and outputs are mostly interchangeable, so you can use other pins, just remember to change your code accordingly

  
• Pin 3 is also a PWM pin which means it can also provide perceived voltage values between 0 and 5v, within a scale of 0 to 255