A flash ADC (Analog-to-Digital Converter) is a type of converter that quickly transforms an analog signal into a digital signal. It uses a parallel approach, employing multiple comparators to simultaneously compare the input voltage against reference voltages. This allows it to achieve very high conversion speeds, making it ideal for applications requiring rapid data processing. Flash ADCs are commonly used in high-speed applications such as digital oscilloscopes, radar systems, and video processing. While they offer fast conversion times, they can be more expensive and consume more power than other types of ADCs, like successive approximation ADCs or sigma-delta ADCs.