5.2 Problem 2: You performed well in you last design assignment at Ford Motor Company, so you still retain your job there. Today your manager asked you to design the switch which starts and stops the car's air conditioning system. The requirement is given as- "....When the a/e button is pushed it should start the a/e, pushing this button for the second time should stop the a/c. The button also incorporates a built-in green LED which glows when the a/c is opcrating, and remains off otherwise. This switch signals the car's main control logic to turn on the relay which switches en the a/c compressor..." You asked one of your senior colleagues to help you get started. He told you that this kind of button functionality is known as a toggle push button". He also told you that as Ford is facing competition to cut costs, it would be better to use a "normally off (push-to-make) illuminated push button (SPST, NO to implement this toggle push button (which is cheaper and more reliable), rather than using a costly and less reliable mechanical toggle button. This kind of push button with built-in LED (for illumination) is available in the market. The "SPST NO illuminated push button switch" which you finally choose has four terminals two for the switch, and other two are for the LED which has a register in series (to limit the current through the LED), you can apply 3 to 5 V to the LED terminal to illuminate the LED. Hint: Different types of switches are described in the below link- Activities to do- . What is the meaning of "SPST" and "NO in the context of electro-mechanical switches? 2. Design a small digital circuit (with Logisim) using basic logic gates, so that when this circuit is used with the chosen switch, it will make the circuit function as a toggle switch. Use the button component in Logisim for this question. (Input/Output> Button) The way the button switch operates in Logisim, as long as you keep the button pressed an LED or other output signal will stay ON. When you release the button, the LED or output signal goes OFF. Design a toggle switch such that when you press the button once, your LED turns ON and then remains ON (even after the button is released) until the button is pushed again Using the text-insert feature in Logisim mention in the circuit the chip number(s) (from the 74XX family) that you would use for the circuit and identify the pin numbers that would be used by your circuit 3. 5.2 Problem 2: You performed well in you last design assignment at Ford Motor Company, so you still retain your job there. Today your manager asked you to design the switch which starts and stops the car's air conditioning system. The requirement is given as- "....When the a/e button is pushed it should start the a/e, pushing this button for the second time should stop the a/c. The button also incorporates a built-in green LED which glows when the a/c is opcrating, and remains off otherwise. This switch signals the car's main control logic to turn on the relay which switches en the a/c compressor..." You asked one of your senior colleagues to help you get started. He told you that this kind of button functionality is known as a toggle push button". He also told you that as Ford is facing competition to cut costs, it would be better to use a "normally off (push-to-make) illuminated push button (SPST, NO to implement this toggle push button (which is cheaper and more reliable), rather than using a costly and less reliable mechanical toggle button. This kind of push button with built-in LED (for illumination) is available in the market. The "SPST NO illuminated push button switch" which you finally choose has four terminals two for the switch, and other two are for the LED which has a register in series (to limit the current through the LED), you can apply 3 to 5 V to the LED terminal to illuminate the LED. Hint: Different types of switches are described in the below link- Activities to do- . What is the meaning of "SPST" and "NO in the context of electro-mechanical switches? 2. Design a small digital circuit (with Logisim) using basic logic gates, so that when this circuit is used with the chosen switch, it will make the circuit function as a toggle switch. Use the button component in Logisim for this question. (Input/Output> Button) The way the button switch operates in Logisim, as long as you keep the button pressed an LED or other output signal will stay ON. When you release the button, the LED or output signal goes OFF. Design a toggle switch such that when you press the button once, your LED turns ON and then remains ON (even after the button is released) until the button is pushed again Using the text-insert feature in Logisim mention in the circuit the chip number(s) (from the 74XX family) that you would use for the circuit and identify the pin numbers that would be used by your circuit 3
