PURPOSE: A fly back transformer is provided to prevent the fly back transformer from being blown owing to an over current generated at the primary coil by opening the primary coil while the over current flowing at the primary coil. CONSTITUTION: A pulse voltage at the primary winding coil(L1) is boosted as a pulse voltage at the secondary winding coil(L2) in accordance with an operation of a horizontal outputting portion(11). After rectifying through a rectifying diode, the pulse voltage is smoothed by means of a high voltage capacity(CH) and then the smoothed high voltage is applied to an anode of a Braun tube. Thereafter, the high voltage is divided again by means of pluralities resistance. Then, the divided voltage is properly controlled and is provided as a focus voltage(VF). Resistance(R) is installed at the primary winding coil(L1). This resistance(R) is disposed in series at the middle portion of the primary winding coil(L1).
展开▼
