| 摘要 |
PURPOSE:To improve the reliability in the detection by connecting a water content detecting electrode to the winding of a transformer composing a transformer feed back type oscillation circuit to insulate the electrode and the circuit with the transformer. CONSTITUTION:A transformer feedback type oscillation circuit is so constructed that a part of an output of an amplifier 7 is fed back positively to the input side of the amplifier 7 through the windings N1 and N2 of a transformer T. Electrodes 5 and 6 as water detection terminal are connected to the winding N3 of the transformer. With such an arrangement, when there is no water between the electrodes 5 and 6, and impedance Z to the electrodes 5 and 6 from the winding N3 becomes an open-circuit impedance which causes little loss in the oscillation circuit. Thus, an output signal of the oscillation circuit is generated at an output terminal 8. However, some water content between the electrodes 5 and 6 reduces the impedance Z, which increases loss in the oscillation circuit thereby lowering the output level. |
