Electronic timer e.g. for corridor light - has digital module inserted in power line before socket outlet to allow switching off after set interval

摘要

The time control includes two leads taken from the live and neutral power supply lines (2). These pass through two fuse elements (3), and the live lead then passes through a main switch (4) to a timer (5). The timer controls the supply of power to a lamp or appliance (6). The timer has a digital electronic circuit, deriving its time-keeping from the 50 Hz supply. It is thus insensitive to temperature variations, or variations in the load taken from the output.