Explanation: Time-Base Control in a Cathode Ray Oscilloscope (CRO) Definition: The time-base control in a Cathode Ray Oscilloscope (CRO) is a critical function that ensures the proper horizontal deflection of the electron beam across the screen. The primary purpose of the time-base control is to regulate the horizontal sweep speed, which allows the oscilloscope to display signals in a time-coherent manner. This means it provides a consistent time axis on the screen, enabling users to accurately analyze the waveform's time-dependent characteristics.