| 摘要 |
PURPOSE:To insulate a display device electrically and easily by using an ultrasonic wave generator for a thyristor trouble detector. CONSTITUTION:When partial thyristors in the thyristor sections 3a, 3b of a thyristor group 3 are broken and short-circuited, voltage is generated between output terminals (e), (f) when thyristor inverse voltage is applied between the input terminals (c), (d) of a bridge circuit 5, and the ultrasonic wave generator 10 is operated by the voltage and transmits ultrasonic waves. The ultrasonic waves are received by an ultrasonic wave receiver 11, and a display lamp 9 is lit. Accordingly, noises are prevented approximately and the circuit can completely be insulated by using the ultrasonic waves as the transmitting means of trouble signals. |
