| 摘要 |
An electronic time based control system for, for example, a domestic household, comprises a master unit 10 which is connected to a number of slave units 40 via the electrical mains circuit of the household. The slave units 40 are interposed between the main circuit and various domestic appliances whereby operation of the appliances is governed by control information generated by the master unit which, in turn, is programmable by the user so that the control signals for different appliances can be produced at pre-settable times. In their simplest form, each slave unit may comprise circuitry for detecting and unscrambling control information intended for that slave unit and a power switching element such as a triac for regulating electrical power supply to the associated appliance. Such a slave unit may be housed within the electrical plug for connecting the appliance to the mains circuit thereby obviating the need for a separate housing for each such slave unit. The control information will be superimposed on the mains supply wave form and to avoid interference between separate systems operating on the same general mains supply network, the fuse connection between the general network and the household mains circuit may incorporate a filter for preventing control signals produced by the master unit from passing into the general supply network. |
