Indicator circuit including a bridge circuit with means for error indication independent of voltage source variation.

摘要

An indicator circuit has an output corresponding to the departure of a sensed condition from a particular condition. The circuit provides digital representation of an anaiogue error voltage present as an output of a bridge circuit 10 where the digital representation is independent of variation in supply voltage V to the bridge circuit. The circuit includes a capacitor 29 arranged to be charged from an initial voltage VREF representative of the "zero" point of the analogue error voltage range to a full-scale error voltage in the amount of time that it takes for a digital counter 51 to count from zero to full scale. The capacitor voltage Vc is compared to the error voltage Vt in a comparator 40 to stop the count upon equality.