| 摘要 |
PURPOSE:To detect the resistance of a high-tension cord without detaching the cord from a high-tension circuit, by extracting the time constant of discharge in an induction discharge region of a secondary voltage signal detected from an ignition circuit, and detecting the resistance of the high-tension cord from the time constant of discharge. CONSTITUTION:A detecting citucit 1 detects a high, secondary voltage V2 from an engine igniting circuit of an automobile or the like, and the output of the circuit 1 is applied to a differentiation circuit 2, where the time constant tau of discharge in the secondary voltage V2is extracted. The differential output of the circuit 2 is converted into a pluse signal c proportional to the duration of the differential output in a waveform shaping circuit 3 and then applied to an integration circuit 4. The circuit 4 converts the output c of the circuit 3 into a voltage signal d proportional to the width of the pulse signal c, and the output of the circuit 4 is in turn applied to a peak holding circuit 5 for hilding the peak value for a certain time period. This periopd is determined by the output of a reset-signal generating circuit 6, and the output of the circuit 5 is shown by an indicating circuit 7 as the resistance value of the high-tension cord. |
