| 摘要 |
PURPOSE:To eliminate one unit of the Zener diode as well as to increase the reliability by securing more than two kinds of performance for one unit of the Zener diode. CONSTITUTION:The power switch is turned on, and the fixed potential is applied to +B2 through resistor 12 along with the current flowed to Zener diode 1. On the other hand, E-B of transistor Tr8 is cut off since it functions the backward diode at the side of the low-voltage circuit, and the constant voltage is generated across diode 1 to actuate the horizontal oscillation circuit. As a result, the pulse is generated to output winding 10b of FBT and then rectified by diode 3 and capacitor 4. While the base of Tr9 features the constant voltage via the voltage at both ends of diode 1 as well as the forward voltage of B-E of Tr8, and the constant voltage power source lower than the base potential by the amount equivalent to the B-E forward voltage is obtained at the emitter of Tr9 through collector resistance 17 to be supplied to the low-voltage circuit. Furthermore, diode 1 is utilized to amplify the error. In case the X-ray protective circuit exists, the increasing voltage of winding 10b is detected to operate the protective circuit, thus preventing the secondary breakdown for resistance 17, FBT10, diode 3 others. |
