Question

Two car garages have a common gate which needs to open automatically when a car enters either of the garages or cars enter both. Device a circuit that resembles this situation using diodes for this situation.

Answer 1

Hint: The logic gates includes the OR gate, AND gate, NOR gate, NAND gate and NOT gate. Out of which the NOR gate, NAND gate and NOT gates are the negative logic gates. They have a wide range of applications in a day to day life, out of which the given question is also one of those.

Complete solution:
From the given data, it is clear that the garages should open automatically when a car enters either of the two garages. This condition is fulfilled by the OR gate. This is because the gate provides the output $1$ , when any one of the input is $1$ or if both the input is $1$.
But if both the output is $0$ , then the result will also be $0$ . That is if a car enters any one of the garages or if the car enters both the garages the doors will be opened automatically, else the garages will be closed. The below table shows the condition of the OR gate.

Input 1	Input $2$	Output
$0$	$0$	$0$
$0$	$1$	$1$
$1$	$0$	$1$
$1$	$1$	$1$

Hence the OR gate resembles this situation of the car garages.

Note: On the other hand, let us take the AND gate in this situation. If the logic gates AND is used, then the garages will be automatically open only if the car enters both the garages at a time. Hence the AND gate is not the answer for this condition.