| 摘要 |
<p>PURPOSE:To simplify a control circuit by standardizing constituent parts by one system by selectively driving electromagnetic change-over switch contacts according to the time width of a burst signal having a single frequency. CONSTITUTION:As a control signal a burst signal sequence of time width tau having a single carrier frequency f1 is used. A monostable multivibrating circuit 31 is given a time constant tau0. When tau=tau1<=tau0, the transistor TR33 of a Schmitt trigger circuit 30 turns on and the TR34 turns off; and the TR35 of the monostable multivibrating circuit 31 turns on and the TR37 turns off. Therefore, a TR42 turns off, and a TR43 turns off; and a TR50 turns off to flow a current to an energizing coil 48 only for a time tau0. When tau=tau2<tau0, on the other hand, the TRs operates as mentioned above up to the tau0; after the tau0, the TR35 turns off, the TR37 off, the TR34 off, and the TR42 on to flow a current to a coil 45 only for the time tau-tau0. Therefore, a diode 53 turns on only when the current flows through the coil 48, and its terminal resistance value varies, so the operation of an electromagnet energizing circuit for contact selection of a control circuit is confirmed.</p> |
