Electronics and Communication Engineering - Exam Questions Papers - Discussion

Two products are sold from a vending machine, which has two push buttons P₁ and P₂. When a button is pressed, the price of the corresponding product is displayed in a 7-segment display. If no buttons are pressed, '0' is displayed, signifying 'Rs' .0'. If only P₁ is pressed, '2' is displayed, signifying 'Rs. 2'.
If only P₂ is pressed, '5' is displayed, signifying 'Rs. 5'.
If both P₁ and P₂ are pressed, 'E' is displayed, signifying 'Error'. The names of the segments in the 7-segment display, and the glow of the display for '0', '2', '5' and 'E', are shown below.

Consider

1. push button pressed/not pressed is equivalent to logic 1/ 0 respectively
2. a segment a to g are considered as functions of P₁ and P₂, then which of the respectively.

What are the minimum number of NOT gates and 2-input OR gates required to design the logic of the driver for this 7-segment display?