| 摘要 |
PURPOSE:To increase the number of relay which is connected to the same channel by using a tri-state output buffer circuit as a driver for a control relay which short-circuits and separates a couple of contactors as two electrodes. CONSTITUTION:For example, a switch 5a for short-circuit point selection and a short-circuit latch switch 6 which latches the signal of the switch 5a are turned on to generate a control signal through an AND gate 10a which ANDs the outputs of the switches 5a and 6, an FF12a which is set by its AND output, an OR gate 13a which ORs the output of the switch 5a and the output of the FF 12a, etc. The control signal is impressed to a tri-state output buffer 5 specified with a switch 6a for selection, etc., and the relay 4 is driven through the buffer 15 to short-circuit the couple of contactors of a test plug 1. Instantaneous short-circuiting is performed similarly, and a power switch for selection is not necessary for a large-capacity channel because the tri-state output buffer is used, so that the number of relays of the same channel is increased.
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