To investigate a circuit which simulates addition of 2 binary digits.
One SK-50 breadboarding socket
One 7486 TTL integrated circuit
One 7408 TTL integrated circuit
Two 470 OHM resistors
One 9V Battery
Assemble the circuit on the breadboard. (Note pins 1 and 2 are at 5 volts when they are not connected)(Note: In the schematic above if 2 wires are crossed but don't have a large dot, then the wires are not connected. BUT if the wires do have a large dot at the intersection then that means they have to be connected on the breadboard!)
Observe LED 1 and LED 2 for steps (3) to (6)
Connect input A and B to be both high
Connect A as high and B as low
Connect A as low and B as high
Connect both A and B as low
Review the results in chart form of the four cases for adding 2 binary digits.
Compare question 1 with the observations in this experiment.
When 2 digits are added a sum and a carry are obtained. For example 1 + 0 has a sum of 1 and a carry of 0. How should the LED outputs in this experiment be interpreted?
When any 2 numbers with more than 1 digit per number are added, the addition at any place value requires the addition of 2 digit per number are added, the addition at any place value requires the addition of 2 digits from the present place value plus the carry from the previous place value. For example:
Our Circuit will simulate case A. Describe a circuit to simulate case B.
Summarize the circuit requirements to add 2 binary digits.