Resolution, speed and power consumption are the three key parameters for an Analog-to-Digital Converter (ADC) and flash ADCs are the fastest type of ADC. In this paper, an effort is made to design 3-bit and 8-bit flash ADC using multisim. Flash ADC very useful for high-speed applications such as radar detection, wide band radio receivers and communication links. More often the flash ADC is embedded in a large IC containing many digital decoding functions. The integrated flash ADC is operated at 3 and 8-bit precision with analog input voltage of -10.0Vdc to +10.0Vdc.