Circuit for reducing AC components of DC supply to clocked devices in motor vehicle by placing tuned filter in parallel with input to device e.g. DC motor

摘要

A filter (2) which is tuned to the excitation frequency of the clocked device (1) is connected in parallel with the input (11,12) of the device. The filter may be a passive filter, comprising an inductance (23) a resistor (24) and a capacitance (25) connected in series. The filter may be connected directly between the terminals, or remote from the clocked device, or its drive circuitry.