Low voltage sensor with flat plate type capacitor as sensor element

摘要

Capacitor type low voltage sensor (4) has one electrode, the input electrode (6) connected to the low voltage conductor (2) being measured, while its middle electrode (7) acts as the sensor output and is connected to the measurement unit (11). The input electrode comprises two electrode regions (6a, 6b) which are electrically linked and define an electrically shielded region (26) between them. The middle electrode (7) is at the centre of this region (26) and so fully isolated from the outer electrode (6a, 6b). Its connection to the measurement unit (11) is switched between two states, one where it takes a small current from a capacitor energy store and the other where it supplies the signal which is used to determine and display the low voltage value.