Multi-standard line scanning stage for TV set - has voltage dependent tangent correction capacitor with bias varied by standards change switch

摘要

A line output stage transistor (2) is used. It has a line frequency control voltage fed to its base electrode and is connected by way of a winding (3) of the line output transformer and a smoothing resistor (4) and capacitor (5) to a supply voltage (U1) which is selected by a standards selection switch (6). The transistor is also connected to a flyback capacitor (7), the line deflection coils (8), a tangent capacitor (11) and a circuit for the correction of east-west pincushion distortion. A transformer (9) serves to balance the deflection current in the two deflection coils to produce optimal convergence. The tangent correction capacitor capacitance is dependent on the applied voltage, and by variation of the supply voltage to the transistor through the standards changeover switch, an appropriate biassing voltage is selected.