Specifications

CA1 Course Notes
Sharp Electronics (UK) Limited
CE Technical Support GroupPage 56
CA1 Discrete Component Vertical Stage
Unlike the CA10 chassis, the vertical output stage used in the CA1 chassis is a discrete component type
circuit. The circuit descriptions below explain the function and operation of the vertical driver and output
stages. Note that a very similar circuits are used in previous ranges of Sharp small screen television
receivers.
Vertical Driver Stage
IC201 generates the vertical drive and geometry correction signals ( geometry settings contained within
the non volatile memory, IC1002 ). The circuit shown below is the driver stage for the output stage.
Figure 49 : CA1 Vertical Driver Stage
From pin 64 of IC201, the main drive signal enters the base of the driver transistor ( top of circuit ). At the
same time, the correction signal from pin 63 and feedback from the output stage is added to the driver
base via the bottom transistor. The two transistors are housed in the same package to give stable
operation within a wide temperature range.
As the top transistor is used as a emitter follower, its emitter signal will closely follow the base.