Layout Schematic

Problems

1. 
   A variable resistor, called a potentiometer, is shown in Figure P1.1. The resistance is varied by moving a wiper arm along a fixed resistance. The resistance from A to C is fixed, but the resistance from B to C varies with the position of the wiper arm. If it takes 10 turns to move the wiper arm from A to C, draw a block diagram of the potentiometer showing the input
   

variable, the output variable, and (inside the block) the gain, which is a constant and is the amount by which the input is multiplied to obtain the output. An animation PowerPoint presentation (PPT) demonstrating this system is available for instructors at www.wiley.com/college/nise. See Potentiometer. [Section 1.4: Introduction to a Case Study]

Input angle, θ_i(t) ^{+ 50 volts}

A


C
50 volts

Output voltage, v_o(t)
FIGURE P1.1 Potentiometer

2. 
   A temperature control system operates by sensing the difference between the thermostat setting and the actual temperature and then opening a fuel valve an amount proportional to this difference. Draw a functional closed- loop block diagram similar to Figure 1.8(d) identifying the input and output transducers, the controller, and the plant. Further, identify the input and output signals of all subsystems previously described. [Section 1.4: Introduc- tion to a Case Study]
   
3. 
   An aircraft’s attitude varies in roll, pitch, and yaw as defined in Figure P1.2. Draw a functional block diagram for a closed-loop system that stabilizes the roll as follows:
   

The system measures the actual roll angle with a gyro and compares the actual roll angle with the desired roll angle. Theaileronsrespondtotheroll-angleerrorbyundergoing anangulardeflection. Theaircraftrespondstothisangular deflection, producing a roll angle rate. Identify the input and output transducers, the controller, and the plant. Further, identify the nature of each signal. [Section 1.4: Introduction to a Case Study]





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