Power Transistor Developments for Colour CRT Deflection

Todays colour CRT's have lower deflection energy requirements compared to the CRT's of, say, 12 years ago. The reason for this and the consequent reduction in deflection transistor peak current and peak voltage requirements, is the improved tube technology (narrow neck) and also improved deflection yoke design. A typical 22 inch 90 degree colour tv, today, requires the deflection transistor to operate at a peak collector current of less than 3A and a peak retrace voltage of 950V, whereas the older technology required the transistor, BU208, to operate at 4A and 1250V respectively.