North Park Secondary School
Computer Engineering 11 (ICE 3M0)
Digital Lab 15
Binary Subtraction - full subtractor
To investigate a circuit which simulates addition of 2 binary digits plus the carry.
|One SK-50 breadboarding socket
||One 7486 TTL integrated circuit(XOR)
||One 7400 TTL integrated circuit(AND)
||Two 470 OHM resistors
||One 9V Battery
- Plug all the intgerated circuits into the breadboard leaving some room at the right end for resistors and LED's
- Insert the LED's and resistors.
- Connect all ground and 5 volt wires.
- Connect all other pins and then check all connections.
- Use the observation table as a guide in setting the 3 input voltages. (Remember unconnected inputs are high).
- Record your observation of LED1 and LED2 after each step.
- If any problems arise, chech all wiring connection on the bread board against the circuit diagram.
- Review in chart form the results of the eight cases for subtracting 2 binary digits and a borrow.
- Compare question 1 with the observations in this experiment.
- When 2 digits and a borrow are subtracted, a difference and a borrow are obtained. How should the LED outputs in this experiment be interpreted?
Summarize the circuit requirements to subtract 2 binary digits and a borrow in terms of the circuit in experiment 14.
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