What is an LC Filter ?
An LC Filer is a circuit that removes frequencies from a power supply and smooths / cleans it so the equipment being powered gets a clean power source. In FPV sometimes we find our picture being effected by this dirty power supply.
There are many causes of the interference. If the interference is constant its normally rf based, ie your vtx or camera is providing the noise because its constant. If however the interference increases and decreases with the throttle this is down to the ESC. The speed ( frequency ) of the motor directly has an effect on the amount of interference seen.
ESC interference can sometimes be fixed by simply wrapping the servo lead from the ESC round a ferrite ring 5 or more times. In most cases that sorts it out. If not then its time for a LC filter.
What is one ?
An LC is one of the most basic filters going. It comprises of one or more coils and capacitors. What it does is remove frequencies from a voltage but high and low.
Are they new technology ?
Not at all, if you sat in your front room now chances are your looking at 2 or more. Your home speakers have them inside the speaker box, the filter in this case are used for the sound wave frequencies. They are in this case referred to as crossovers. The small speakers in your hifi cant cope well with bass, so an filter is used to remove the low frequencies ( bass ) so they only reproduce the high ones ( Treble. ) The same with the bass speakers, the higher frequencies are removed so it only produces the low bass frequencies. Where stereos crossovers let some selected frequencies through we use them to get rid of all of them.
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