摘要 |
An igniter test unit produces a square wave voltage that is applied across a parallel circuit comprising a first capacitor and a series arrangement of a second capacitor and diodes. An inductance and a thyristor are connected across the first capacitor, in series. When the thyristor is rendered conductive the voltage across the diodes becomes the sum of the voltages across the capacitors, this voltage being applied across the igniter. Switching of the thyristor is controlled such that the voltage is applied to the igniter in increasing steps of 25 volts until the breakdown occurs at the same voltage five times in succession. The voltage across the igniter is determined by applying it across a capacitive divider, one capacitor being discharged in steps, and the number of steps required to reduce the voltage to a reference value is counted.
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