| 摘要 |
PURPOSE:To detect short-circuited and disconnected spots of a converter quickly and accurately by forming a Wheatstone bridge so as to make one arm thereof as one arm of a bridge of a converter using a strain gauge to perform an indication based on an unbalanced output. CONSTITUTION:Terminals of a converter 1 using a strain gauge are connected in the combination of A-B, B-C, C-A or D-A to form one arm of a Wheatstone bridge 3 in response to the operation of a rotary switch 2. At the same time, LEDs D1-D4 or D5-D10 are selected at a display section 7 corresponding to the combination of terminals A-B... with a switch 6 interlocking the switch 2. Short-circuiting is detected by lighting of the LEDs D1-D4 through a pnp-type transistor Tr1 responding to a negative output due to imbalance of the bridge 3 while disconnection at the gauge or the terminals is detected by lighting of the LEDs D5-D10 through an npn-type transistor Tr1 responding to the positive output. With such an arrangement, short-circuited and disconnected spots of the converter using the strain gauge are detected quickly and accurately. |
