Electric power circuit having means for suppressing generation of harmonics flowing back to AC power source

Abstract

An electric power circuit for producing a DC output from an AC output of an AC power source comprises a rectifying circuit to be connected to the AC power source for rectifying the AC output to produce a rectified output, and a smoothing circuit comprising an electrolytic capacitor connected to the rectifying circuit and having an output port to be connected to a load, for smoothing the rectified output to produce a smoothed output as the DC output onto the output port. The DC output is supplied to the load connected to the output port so that a load current flows from the power circuit through the load. In order to reduce harmonic components flowing back to the AC power source due to ripple component included in the load current, a non-linear resistance element having a positive temperature coefficient of resistance is used in a positive one of connection lines connecting the rectifying circuit and the smoothing circuit. Examples of the non-linear resistance element are a tungsten lamp of a vacuum bulb type and of an inert-gas containing bulb type, and a thermistor having a positive temperature coefficient of resistance.

Dependencies are inferred from the claim text.