| 摘要 |
<p>1,201,056. Time control of electric circuits. TEXAS INSTRUMENTS Inc. Sept.22, 1967 [Jan.9, 1967], No.43262/67. Heading G3T. Also in Division H1] Timing apparatus particularly for a programme control of electric circuitry comprises pairs of thermistors 11, 12, 13, &c., connected to power supply lines L 1 , L 2 the thermistors of each pair being electrically connected to one another and being of opposite temperature co-efficients, and the thermistors are so arranged that heat generated in a thermistor of one temperature co-efficient in a pair, e.g. the thermistor P11, is transferred to a thermistor of the opposite temperature co-efficient in an adjacent pair, e.g. to the thermistor N12. Before commencement of the programme cycle the thermistors are in a cool stable state, but on closing a switch PB1 a thermistor PT1 is energized to heat a thermistor N11 having a negative temperature co-efficient and connected in series with a thermistor P11 having a positive temperature co-efficient. Heating of the thermistor N11 causes an increase of current therethrough and a higher voltage to be applied to the thermistor P11 so that the latter self heats, and also heats the thermistor N12 of the adjacent pair. The latter then self heats and returns heat to the thermistor P11 to produce a steep rise in its resistance. The current through the pair P11, N11 is thus reduced so that they return to their stable cool condition. Subsequent pairs P12-N12, P13-N13, &c., become activated in a similar manner so that lamps such as 21, 23, 25 connected to various pairs become energized at different times, either to indicate the condition of the system or to operate photosensitive devices for the programme control of electric circuitry. Additionally a thermistor or thermistors, such as the thermistor TH1, may be provided to sense the heat dissipated from any of the thermistors in the pairs and effect various programming operations. The programming sequence may be made repetitive by closing a switch SW1 to connect in series with the thermistor P11 and a thermistor N11A heated by the thermistor P18 of the final pair. In an alternative system the thermistors are so arranged that each two thermistors between which heat is to be transferred are mounted on a common support. In a further system the thermistors of each pair are electrically connected in parallel.</p> |
