| 摘要 |
<p>1,248,975. Measuring rotation electrically. MATSUSHITA ELECTRIC INDUSTRIAL CO Ltd. Nov. 1, 1968 [Nov. 2, 1967], No. 51819/68. Heading G1N. A rotation sensor, Fig. 6, comprises a rotatable member 1 carrying a rotary single pole double throw switch 2-7, so that a capacitor 11 is alternately discharged (contacts 5 and 7 made) and charged (contacts 5 and 6 made) from a second capacitor 12, the resultant voltage step at point 17 switching-on a transistor 14 which is maintained in a conducting state by charging current for the series combination of capacitors 11 and 12 being drawn through its base, the consequent variation of collector current providing a measure of rotational speed on a device 15, or the switching transition may indicate a cessation of rotation when the device 15 is a warning lamp or a relay coil. An alternative embodiment Fig. 11 is solely to indicate presence or absence of rotation. Above a critical speed, charging current for one or other of the capacitors 33, 34 is drawn through the base electrode of a transistor 28 of which the collector potential maintains a second transistor 30 in a cut-off state thus rendering a warning device 15 in its collector lead inoperative. Below the critical speed the capacitors become fully charged so base current to transistor 28 ceases thereby cutting it off and turning transistor 30 on, the resultant collector current activating the device 15. A by-pass switch 32 renders the circuit inoperative. Figs. 1-5 and 8-10 (not shown) illustrate details of the switch construction.</p> |
