Question 8-30D4

In a Cathode Ray Tube (CRT), an electron beam is used to draw waveforms or images on a screen. To move this beam, deflection systems are employed. The "sweep" refers to the horizontal movement of the electron beam across the screen, creating the time axis for a waveform display. To achieve this horizontal deflection, a pair of deflection coils (or plates in electrostatic CRTs) is used. One coil provides a magnetic field to pull the beam in one horizontal direction, and the other provides a field to push it in the opposite direction. The sweep amplifier generates the varying signal that drives these two coils, causing the beam to move consistently from left to right. A total of two coils are needed to create the push-pull action for a single axis of deflection. While a CRT typically has four coils (two for horizontal and two for vertical deflection), the sweep amplifier specifically drives only the two coils responsible for the horizontal sweep.