Door Control
1. **State the problem:** We have two sensors, A and B, controlling a door. The door opens (output 1) if either sensor A is activated or both sensors A and B are activated.
2. **Construct the truth table:**
| A | B | Door (Output) |
|---|---|--------------|
| 0 | 0 | 0 |
| 0 | 1 | 0 |
| 1 | 0 | 1 |
| 1 | 1 | 1 |
Explanation: The door opens when A=1 regardless of B, so output is 1 when A=1.
3. **Find the final output equation using SOP method:**
From the truth table, the output is 1 for rows where:
- A=1, B=0 (row 3)
- A=1, B=1 (row 4)
The minterms for these rows are:
- Row 3: $A \overline{B}$
- Row 4: $AB$
So, the SOP expression is:
$$
A \overline{B} + AB
$$
4. **Simplify the expression:**
Factor out $A$:
$$
A(\overline{B} + B) = A(1) = A
$$
So, the final output equation is:
$$
\boxed{Y = A}
$$
5. **Logic gate based digital circuit:**
Since the output depends only on $A$, the circuit is a direct connection from sensor $A$ to the door control.
**Summary:** The door opens if sensor A is activated, regardless of sensor B.