| 摘要 |
The door locking device comprises a solenoid actuator (A) associated with a control circuit (1) including: a power source (2), a switch (3) interposed between the power source (2) and the actuator (A), and a heat-sensitive device (4) connected in series with the actuator (A) and adapted to increase its own resistance when its temperature exceeds a predetermined level, so as to limit the current flowing in the actuator (A). The heat-sensitive device (4) is such that in a first temperature range (C1), substantially equal to that of the ambient operating temperature, it has a high impedance which can limit the current flowing in the actuator (A) to a level below that required for its activation; in an adjacent second range (C2) of higher temperatures, it has a reduced impedance which allows sufficient current to flow in the actuator (A) to cause its activation; and in a third range (C3) of even higher temperatures, adjacent to the second range (C2), it has a high impedance which can limit the current flowing in the actuator (A). |
