| 摘要 |
A power line-operated electronic time-clock including a clock switching circuit, a memory for storage of switching or alarm times, including an input device and a display device, and a power outage-bridging circuit for supplying electrical energy during a power outage to at least the timing components of the clock switching circuit and when required, to the memory storage device. The time-clock includes a monitoring circuit that is interconnected to the memory storage device, and the power outage-bridging circuit for generating a blocking signal in response to the absence of timing data being introduced into the memory device for rendering the power outage-bridging circuit inoperative. Thus, the energy storage device within the power outage circuit will not be drained prior to use or during testing of the clocks. In addition, the monitoring circuit may generate the blocking signal subsequent to a predetermined time interval after a power outage to disconnect the time clocks to prevent drainage of the energy storage device over an extended power shut down.
|
