PURPOSE: To enlarge a video display size in a vertical direction without increasing the loss of a vertical output amplifier at the time of displaying at a wide mode by providing a normal mode vertical oscillation circuit and a wide mode vertical oscillation circuit and switching outputs.
CONSTITUTION: The vertical oscillation circuits 21 and 22 which can respectively output a normal mode vertical saw tooth wave and a wide mode vertical saw tooth wave are provided for a vertical deflection circuit. Then, the vertical saw tooth waves corresponding to respective modes are inputted to a vertical output amplifier 5 and it causes a vertical deflection current which is almost the same form as the vertical saw tooth wave to flow to a vertical deflection coil 6. Consequently, the saw tooth wave current having optimum amplitude and fly-back period is caused to flow in the vertical deflection coil 6 at the time of displaying at the normal mode and the wide mode. Thus, the amplitude of the vertical deflection current can be held at constant at the normal mode and the wide mode.
TAJIMA HISANOBU
OSAWA MICHITAKA
Next Patent: DEVICE FOR POSITIONING SLIDING CORE