Minimum number of comparators required to build an 8-bit flash ADC:

To understand the minimum number of comparators required to build an 8-bit flash ADC, let's first understand the working principle of a flash ADC and how it converts an analog input signal into a digital output.

Working Principle of a Flash ADC:
A flash ADC, also known as a parallel ADC, is a type of analog-to-digital converter that uses a combination of comparators to convert an analog input signal into a digital output. The input signal is compared to multiple reference voltages simultaneously, and the output of each comparator is used to directly generate the digital output.

Binary Encoding:
In an 8-bit flash ADC, the digital output is represented in binary form. Each bit represents a voltage range, and the output of each comparator determines whether the input signal is greater or less than the corresponding reference voltage.

Number of Comparators:
The number of comparators required for an 8-bit flash ADC can be calculated using the formula:
Number of Comparators = 2^n - 1

Where 'n' is the number of bits. In this case, n = 8.

Calculation:
Number of Comparators = 2^8 - 1
Number of Comparators = 256 - 1
Number of Comparators = 255

Therefore, the minimum number of comparators required to build an 8-bit flash ADC is 255.

Conclusion:
An 8-bit flash ADC requires a minimum of 255 comparators to accurately convert an analog input signal into a digital output. Each comparator compares the input signal with a specific reference voltage, and their outputs are combined to generate the digital representation of the input signal.