| 摘要 |
PURPOSE:To identify the trouble position and the number of troubles by providing a circuit for detecting the forward or reverse voltage across a thyristor between the A and K of the thyristor and judging the presence or absence of the voltage during non-conducting period of the thyristor. CONSTITUTION:When a current flows through photodiodes PDi which are connected in anti-parallel with each other, i.e., when a voltage is applied between the A and K of a thyristor Si, a light signal is emitted. This light signal is led through a light guide LGi to a trouble diagnosing device FM. A-K voltage detector VLi has a limiting resistor Rei and a series connection circuit of the photodiodes PDi. If forward or reverse current flows across the thyristor Si during non-conducting period of the thyristor Si in this detector, the thyristor Si is normal, but if not, it is judged as being in trouble, thereby identifying the trouble position and the number of the troubles. |
