To investigate a circuit which simulates the ordered subtraction of 2 binary digits.
One SK-50 breadboarding socket
One 7486 TTL integrated circuit(XOR)
One 7400 TTL integrated circuit(AND)
Two 470 OHM resistors
One 9V Battery
Assemble the circuit on the breadboard.
Observe LED1 and LED2 for steps 3 to 6. Be sure to record your observations after each step.
Connect inputs A and B to 5 volts.
Connect inputs A to high and B to low.
Connect inputs A to low and B to high.
Connect inputs A and B to low.
Output 1 LED1 ON/OFF
Output 2 LED2 ON/OFF
Review in chart form the results of the four cases for subtracting 2 binary digits.(Pay attention to the order of subtraction and the borrows that are produced.) Please use the below chart to your discretion for the latter question.(Note: not all cells need to be used)
Compare question 1 with the observations in this experiment.
Explain why an Exclusive OR gate is useful in this experiment.
When 2 digits are subtracted, a sum and a borrow are obtained. How should the LED outputs in this experiment be interpreted?
Explain how the borrow is generated by the circuit in this experiment.
Summarize the circuit requirements to subtract 2 binary digits.