| 摘要 |
PURPOSE:To make small the scale of circuit, by monitoring the change in the output voltage at the voltage application part to the focus grid together with controlling the gate circuit with the result of monitoring. CONSTITUTION:The Zener diode located to prevent the variance of output due to the variance in load is omitted, a registor 18 is inserted in series with a variable resistor 12 through which a voltage is fed to the focus grid, and a failure voltage detecting circuit 13 for monitor is provided at the connecting point between the variable resistor 12 and the resistor 18. With this constitution, since the voltage applied part to the focus grid is taken from the intermediate tap of the secondary winding of a flyback transformer, a voltage proportional to the anode voltage of a CRT is obtained, and further monitoring is made at a circuit 13, and a gate circuit 14 can be controlled according to the result, then both the voltage variance due to load variance and the voltage variance due to voltage abnormal rise can be controlled. |
