| 摘要 |
PURPOSE:To reduce consumption of electricity and prevent an electric shock accident by turning switching elements on under the condition that the positive and negative excitations by an exciting coil are stopped and thereby intercepting an excitation current. CONSTITUTION:The switching elements 17 and 19 are subjected to on-off control by a timing signal from a schmitt trigger circuit 27, whereby the excitation current is supplied periodically to the exciting coil 18 in a measuring pipe. On the occasion, the elements 17 and 19 are turned off by the action of a selfintercepting means 39 under the condition that no timing signal is present for a prescrived period and thereby no excitation current to the coil 18 is supplied. As the result, an influence on other apparatuses using a power source 11 together with the elements is eliminted and consumption of electricity is reduced. |
