| 摘要 |
PURPOSE:To attain polarity inversion of a pulse output voltage with simple circuit constitution by adopting the constitution that two normal relays driven momentarily alternately by an operation signal are used and an output is obtained from each common terminal. CONSTITUTION:When an operation signal is fed to a microcomputer 39, a pulse voltage is outputted to the 1st output port 40, an output of the 1st logic element 37 goes to H only during the output of the pulse voltage, a transistor 33 is turned on, a winding 31 of a relay 21 is excited to connect a common terminal 27 to a normally open contact 25. Thus, a pulse output voltage is induced, which has a polarity where the 1st output terminal 28 is a positive VCC. When the operation signal is fed to the microcomputer 39, a pulse voltage is outputted at the 2nd output port 41, a winding 32 of the relay 22 is excited and the common terminal 29 is connected to the normally open contact, then a pulse output voltage is induced, where the terminal 28 is directed to the negative VCC' with respect to the 2nd output terminal 30.
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