| 摘要 |
PURPOSE:To obtain detection characteristics with good linearity without any dead band by using a bridge whose two sides consist of such detection coils that two coils wound in the same rectangular shape are arranged while one side of the same length of each coil is in contact. CONSTITUTION:The coils 21 and 22 as the detection coils in the same shape are arranged while one side of the same length of each coil is in contact on the same plane. Those coils 21 and 22 constitute the bridge circuit with balance resistors 51 and 52. This bridge circuit is supplied with electric power from a high frequency power source 6, and an output which is zero when a guide line 3 is present right under the coils 21 and 22, or 0 or 180 deg. out of phase according to the distance therefrom to left and right is obtained and passed through a signal demodulation circuit 7 to obtain a zero-position detection sigal 71 which has characteristics as shown in a figure. |
