FUN WITH DIGITALS. Experimental Examination, IMSO 2007, Jakarta, 14 November 2007 Name: ; Country:

Transcription

1 FUN WITH DIGITALS Mrs. Ana is driving her new car which is equipped with a good safety system. The engine of the car can only be started if its doors are locked and the seat belt is fastened. If both conditions are not fulfilled, the engine can not be started. In science, those conditions are described by the AND logic. Many buildings are equipped with fire detection alarm system. The alarm will be automatically turned on if the system detects smoke, or the fire alarm button is deliberately pushed. The alarm will turn on if at least one of the above conditions is fulfilled. In science, those conditions are described by the OR logic. There are many electric appliances such as lights, refigerators, TV and so on in our houses that are equipped with switches to turn them on and off. If the switch is in the ON position, those appliances will turn on because electric current can flow through them. Now, we will play with lamp. The lamp will be turn on and off with the help of digital circuits with AND logic and OR logic principles using switches.

2 Provided electronic kits: 1. One set of main board consisting of : a. a socket for extension board b. a main lamp (actually it is a LED, light emitting diode) c. indicator lamps (LEDs) d. four switches (S1, S2, S3, and S4) e. a buzzer f. batteries in black box Indicator lamps Battery switch Main lamp Batteries Socket Switches 2. Five extension boards (logic boards):

3 ACTIVITY 1 1. Plug the pins on the downside of Board A (AND logic) onto the socket on the main board properly (see the picture below). 2. Set on the batteries by changing the switch on the black box to ON position. Batteries are working properly if the red indicator lamp lights on. 3. The logic board is working properly if the green indicator lights on. 4. In this activity, you will have to change the positions of S1 and S2 switches to ON or OFF according to the Table 1 below. The positions of S3 and S4 are ignored. Write ON in the Main Lamp column (L) if the main lamp lights on, Write OFF in the Main Lamp column (L) if the main lamp lights off. 5. Turn off the batteries by changing the switch on the black box to OFF position after completing the table. Table 1. Board A (AND) No. S1 S2 Main Lamp (L) 1 OFF OFF OFF 2 OFF ON OFF 3 ON OFF OFF 4 ON ON ON (Total Score 4)

4 ACTIVITY 2 1. Unplug Board A and plug Board B (OR logic) onto the socket in the main board properly. 2. Set on the batteries by changing the switch on the black box to ON position. Batteries are working properly if the red indicator lamp lights on. 3. The logic board is working properly if the green indicator lights on. 4. Change the positions of S1 and S2 switches to ON or OFF according the Table 2 below. The positions of S3 and S4 are ignored. Write ON in the Main Lamp column (L) if the main lamp lights on, Write OFF in the Main Lamp column (L) if the main lamp lights off. 5. Turn off the batteries by changing the switch on the black box to OFF position after completing the table Table 2. Board B (OR Logic) No. S1 S2 Main Lamp (L) 1 OFF OFF OFF 2 OFF ON ON 3 ON OFF ON 4 ON ON ON (Total Score 4) Question 1 : From the Table 1 and Table 2, explain how the AND logic and the OR logic work? Answer: AND logic if at least one of the inputs is OFF then the output is OFF If both inputs are ON then the output is ON OR logic if at least one of the inputs is ON then the output is ON If both inputs are OFF then the output is OFF (Score 4) ACTIVITY 3

5 You are requested to find the unknown logics (X1 and X2) on the Board C. 1. Unplug Board B and plug Board C onto the socket in the main board properly. 2. Set on the batteries by changing the switch on the black box to ON position. Batteries are working properly if the red indicator lamp lights on. 3. The logic board is working properly if the green indicator lights on. 4. Change the positions of S1, S2 and S3 switches to ON or OFF a according the Table 3 below. The position of S4 is ignored. For each arrangement of S1, S2 and S3, write ON in the Main Lamp column (L) if the main lamp lights on, and write OFF if the main lamp lights off 1. Turn off the batteries by changing the switch on the black box to OFF position after completing the table. Table 3. Board C No. S1 S2 S3 Main Lamp (L) 1 OFF OFF OFF 2 OFF OFF ON 3 OFF ON OFF 4 OFF ON ON 5 ON OFF OFF 6 ON OFF ON 7 ON ON OFF 8 ON ON ON (Score 8) Question 2: Use the Table 3 to answers the following questions: (a) What is the logic of X1, is it AND or OR? Explain your answer. AND (Score 2) (b) What is the logic of X2, is it AND or OR? Explain your answer.

6 (Score 2)

7 ACTIVITY 4 You are requested to find the unknown logics (X3, X4 and X5) on Board D. 2. Unplug Board C and plug Board D onto the socket in the main board properly. 3. Repeat step 2 to step 3 in Activity Change the positions of S1, S2, S3 and S4 switches to ON or OFF according to the Table 4 below. You are free to select the combination of S1, S2, S3 and S4 positions for each empty row in Table 4. For each arrangement of S1, S2, S3 and S4, write ON in the Main Lamp column (L) if the main lamp lights on, and write OFF if the main lamp lights off. Table 4. Board D No. S1 S2 S3 S4 Main Lamp (L) 1 OFF OFF OFF OFF 2 OFF OFF OFF ON 3 OFF OFF ON OFF 4 OFF OFF ON ON 5 OFF ON OFF OFF 6 OFF ON OFF ON 7 OFF ON ON OFF 8 OFF ON ON ON 9 ON OFF OFF OFF 10 ON OFF OFF ON 11 ON OFF ON OFF 12 ON OFF ON ON 13 ON ON OFF OFF 14 ON ON OFF ON 15 ON ON ON OFF 16 ON ON ON ON (Score 16)

8 Question 3 : Use the Table 4 to answers the following questions: (a) What is the logic of X3, is it AND or OR? Explain your answer. (Score 2) (b) What is the logic of X4, is it AND or OR? Explain your answer. (Score 2) (c) What is the logic of X5, is it AND or OR? Explain your answer. (Score 2)

9 ACTIVITY 5 You are requested to find the unknown logics (X6, X7 and X8) on Board E. 1. Unplug Board D and plug Board E onto the socket in the main board properly. 2. Repeat step 2 to step 3 in Activity Change the positions of S1, S2, S3 and S4 switches to ON or OFF. You are free to select the combination of S1, S2, S3 and S4 positions for each empty row in Table 4. For each arrangement of S1, S2, S3 and S4, write ON in the Main Lamp column (L) if the main lamp lights on, and write OFF if the main lamp lights off. Table 5. Board E No. S1 S2 S3 S4 Main Lamp (L) (Score 8)

10 Question 4: Use the Table 5 to answers the following questions: (a) What is the logic of X6, is it AND or OR? (Score 1) (b) What is the logic of X7, is it AND or OR? (c) What is the logic of X3, is it AND or OR? (Score 1) (Score 1)

11 ACTIVITY 6 In this activity, you are requested to fill in the blank in the Table 6, based on the combination of two OR logics and one AND logic as shown below. Table 6. No S1 S2 S3 S4 Main Lamp (L) 1 OFF.. (OFF) ON OFF OFF 2 ON OFF ON OFF.. (ON) 3 ON ON.. (OFF) ON OFF (Score 3) ACTIVITY 7 In this activity, you are requested to fill in the blank in the Table 7 based on the combination of one OR logic and two AND logics as shown in the diagram below. Table 7 No. S1 S2 S3 S4 Main Lamp (L) 1.. (OFF).. (ON).. (ON).. (ON) ON 2.. (ON).. (OFF).. (ON).. (ON) ON 3.. (ON).. (ON).. (ON).. (ON) ON (Score 6)

12 ACTIVITY 8 1. Unplug Board E and plug Board Z onto the socket in the main board properly. 2. The Buzz will create a sound only for a single combination of switches S1, S2, S3 dan S4. In this activity have to find the right combination the switches. S1 S2 S3 S4 Main Lamp (L).. (ON).. (OFF).. (OFF).. (ON) ON (Score 2) -- Well done! --