ENGG 1015 Tutorial n n n Revision tutorial

ENGG 1015 Tutorial n n n Revision tutorial 11 Dec Learning Objectives q n Prepare for the examination News q Examination n q q Closed book; Need to bring calculators SETL (Online evaluation) HW 2, HW 3 1

To Refresh Your Memory n In the semester, you have learnt… q q q Combinational Logic – Truth table/schematics/Boolean expression, SOP/POS, De. Morgan’s Theorem, K-Map, adder structure Sequential Circuit – Flip flop, Finite State Machine, clock and timing Electrical Circuit – Primitives, KCL/KVL, series/parallel connection, voltage/current divider, loading and buffer Operational Amplifier – Non-inverting amplifier Signals, Systems, Control – Signal flow graph, difference equation, operators, z-transform, feedback control Computer Systems – Binary representation, addition/subtraction for integers, 2’s complement 2

Past Papers n n n n (E: Examination; H: Homework) Systems: 11 H 1 Q 1/Q 2, 10 H 1 Q 1/Q 2 Combinational logic: 11 EQ 5, 10 EQ 5, 11 H 2 Q 5/Q 6, 10 H 2 Q 5/Q 6, 11 H 3 Q 1/Q 2/Q 3, 10 H 3 Q 1/Q 2/Q 3 Sequential logic: New Electrical circuit: 11 EQ 3, 10 EQ 2, 11 H 1 Q 3/Q 4/Q 5/Q 6, 11 H 1 Q 4/Q 5/Q 6/Q 7 Signals and control: New Computer system: 11 EQ 6, 10 EQ 6, 11 H 2 Q 4, 10 H 2 Q 3/Q 4 3

Lab n n n (L: Lab; C: Checkoff) Combinational logic: L 1 C 1/C 2/C 3, L 2 C 1/C 2/C 3 Sequential logic: L 3 C 1/C 2/C 3 Electrical circuit: L 4 C 1/C 2, L 5 C 1/C 2/C 3, L 6 C 1/C 2/C 3 Signals and control: L 7 C 1/C 2/C 3, L 8 C 1/SC Computer system: N/A 4

Block Diagrams for Control (1) 5

Block Diagram for Control (2) n Let the controller C(z) be “A”, the system P(z) be “C”, and the sensor G(z) be “D”. n First-order system with one pole at 6

Block Diagram for Control (3) n Let C(z) be “B”, P(z) be “C”, and G(z) be “B”. n A second-order system with two poles at 7

Smart Air-conditioner Control (1) n n Let Troom be the current room temperature. Also, define TUTH and TLTH be two threshold voltages set by the user, where TUTH >TLTH. When Troom > TUTH, AND compressor is off, then the compressor of the air-conditioner should turn on to lower the room temperature. When Troom < TLTH, AND compressor is on, then compressor of the air-conditioner should turn on, and the room temperature rises. Otherwise, the operation of the compressor stays unchanged. 8

Smart Air-conditioner Control (2) n Using the digitized information DL and DH about the room temperature, implement the air-conditioner control as a state machine. q q Your state machine should have 1 single output called ON. The air-conditioner compressor is turned on only when ON is TRUE. Construct based on logic 9

Smart Air-conditioner Control (3) n n n If instead we want to set the temperature to be lower, with TUTH = 24 and TLTH = 22, suggest a way to achieve this adjustment. Upper comparator: 6 V to input B Lower comparator: 2. 4 V to input B R 1 R 2 n R 1 = R - R 2 = 0. 6 R 10

Bidirectional Motor Driver (1) n Using your knowledge from labs and lectures, complete the following circuit to drive a motor in both directions depending on the value of the potentiometer. 11

Bidirectional Motor Driver (2) n n Referring to the bidirectional motor driver circuit, let k. A be the gain of the non-inverting amplifier on the left. Show that within the operating range of this circuit (i. e. , no saturation), a change in Vp by ∆Vp results in a change of Vmotor by k. A∆V p. 12

Bidirectional Motor Driver (3) n 13

Circuits and Sensors (1) n n In this QTI circuit, we assume that R 0 is 500Ω and that Rir is maximum when it is dark (Rmax = 1 k Ω). When it is bright, Rir is minimum (Rmin = 100 Ω). Note that Vcc is 12 V. The datasheet of the lamp states that it only turns on when the voltage across the lamp (VL) > 5 V. Each lamp has an internal resistance of 1 kΩ. The goal is to turn on a lamp when it is dark. One of your team members suggests connecting the terminal red directly to the lamp, terminal white to Vcc terminal black is grounded. Will this configuration work? 14

Circuits and Sensors (2) n n n Let RL be the resistance combining Rir and the resistance of the lamp, put in a parallel configuration. When it is dark (Rmax = 1 kΩ), the total loading resistance is RL = 500Ω, and therefore the voltage across the lamp (VL) is 6 V. This is enough to turn on the lamp. When it is bright, Rmax = 100Ω and RL = 90. 9Ω. Thus, the lamp is off. 15

Circuits and Sensors (3) n n n Now you have to connect two more lamps in parallel with the first one (i. e. 3 lamps in total). What is the problem? The total loading resistance (when it is dark) will become RL = 250Ω (Parallel connection of resistors), and therefore VL = 4 V. Therefore, it is not enough to turn on the lamps. Therefore, a buffer should be used. 16

Circuits and Sensors (4) n How the buffer should be connected? 0 Vp 0 0 17

Difference Equations (1) n n n Difference equation: Transfer function: Poles: 18

Difference Equations (2) n Partial fraction: n Impulse function: 19