# Circuits in SSI -- II

Start off by reviewing a two chips you saw in Lab 6.

- 7404
- Hex inverter
- 7400
- Quad 2-input NAND gates

We'll use them in this lab to implement the half adder shown below.

## Task 1

Your lab instructor will get you started by showing you how to make input
switches and output LED's. *Warning:* The LED's you use in this lab
are *not* normal LED's. These LED's have built-in current limiting
resisters. If you try this at home, be sure to use resisters.

## Task 2

Figure out how to use one 7404 and one 7400 to implement the circuit.
Construct a wiring diagram and show it to your lab instructor.

7404 7400
+---\/---+ +---\/---+
1 -|1A Vcc|- 14 1 -|1A Vcc|- 14
2 -|1/Y 6A|- 13 2 -|1B 4A|- 13
3 -|2A 6/Y|- 12 3 -|1/Y 4B|- 12
4 -|2/Y 5A|- 11 4 -|2A 4/Y|- 11
5 -|3A 5/Y|- 10 5 -|2B 3A|- 10
6 -|3/Y 4A|- 9 6 -|2/Y 3B|- 9
7 -|gnd 4/Y|- 8 7 -|gnd 3/Y|- 8
+--------+ +--------+

## Task 3

Following the guidence of your instructor build the halfadder with the
7404 and 7400. *Before you power-on your circuit*, have it checked by
one of your labmates.

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