Avoid the harm of harmonic filter circuit and ripple, but many still do not link them works. Harmonic simply put, is the role of a certain frequency voltage or current in non-linear load, it will produce different from the original frequency of other frequency sinusoidal voltage or current phenomenon. Refers to the ripple DC voltage or current, the AC component is superimposed on the DC stabilizing amount. In addition to the circuit, we need to understand the harmonic control of the situation, but also need to know its main hazards:
 
    1, the measurement and measurement instruments, meters can not correctly indicate or measure;
    2, so that the power grid caused by resonance over-current or over-voltage caused by the accident;
    3, add an additional loss, reducing efficiency and equipment utilization for power generation, transmission and electrical equipment;
    4, so that relay protection, automatic devices, computer systems and a lot of electrical equipment is not functioning properly, or does not operate normally or operation;
    5, so that the electrical equipment (such as rotary motors, capacitors, transformers, etc.) is not functioning properly, accelerated insulation aging, thus shortening their life;
    6, interfere with communications systems to reduce the transmission quality of the signal, disrupting the normal signals are transmitted, and even damage communications equipment.
 
Ripple harm:
    1, reducing the efficiency of the power supply;
    2, can interfere with digital logic circuits, affecting its normal work;
    3, easy to produce harmonics on electrical appliances, and harmonics will produce more harm;
    4, strong ripple will cause the generation of surge voltage or current, resulting in burning appliances;
    5, will bring noise, image equipment, audio equipment does not work properly.
    In short, they appear are harmful in a place we do not, we need to avoid. For ways harmonic control and ripple control are many, but wanted to be completely eliminated, seems to be very difficult to do, and we can only be controlled within a permissible range, and do not impact the environment and equipment even reached our purposes.