| 摘要 |
PURPOSE:To prolong the life of a power switch by intermitting the output of a battery power source which is supplied through the primary coil of a transformer by a transistor (TR). CONSTITUTION:A switch 70 is turned on to supply a source voltage from the battery 10 respective gates and a plus voltage is applied to a NOT gate 63 through a resistance element 73 to place respective parts in operation. Conse quently, a rectangular wave oscillator 20 outputs a rectangular wave with 1/2 duty. This rectangular wave drives the TR 32 through an amplifier 31. Conse quently, the output of the battery 10 is intermitted through the primary coil 34 of the transformer 33 and boosted by the transformer 33. The boosted voltage led out of the secondary coil 35 is rectified 40 to a double voltage, which is applied to the insulation resistor 90 to be measured as a DC output high voltage E0 through measurement terminals E and L, so that a current flowing through the resistor 90 is converted 81 logarithmically and outputted on an indicator 80. A current flowing to a control circuit 60 composed of a C-MOS logic circuit is small, so even when this current is intermitted, no spark is generated at the switch 70, whose life is prolonged.
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