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I want to build an LC-Filter from a tutorial I found (German language, if anyone is interested, I'll add a link).

In that tutorial, a 330uH Coil with a max amp of 1A is used.
I have some 330uH coils lying around, but they've only 450mA.

The consumer device will draw up to 700mA.
Is it possible, to put the coils in parallel, like in that schematic?

For a better understanding, what exactly will happen if I do this?

schematic

simulate this circuit – Schematic created using CircuitLab

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    \$\begingroup\$ You can review en.wikipedia.org/wiki/Inductor and look at the section titled "Inductor networks" to see how both parallel and series combinations work. \$\endgroup\$
    – Tyler
    Commented Apr 28, 2016 at 12:30
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    \$\begingroup\$ Your solution is almost correct, you need to use two 660uH in parallel to make a 330uH equivalent. \$\endgroup\$
    – lucas92
    Commented Apr 28, 2016 at 12:44
  • \$\begingroup\$ Since it's a copter application where every gram counts, I'd be tempted to benchmark your 450mA coil at 700mA. Chances are it won't overheat too much. \$\endgroup\$
    – Dmitry Grigoryev
    Commented Apr 28, 2016 at 13:55

2 Answers 2

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To make 330 uH from several 330 uH inductors requires, as a minimum, four devices - two in series gives 660 uH and then two parallel branches of two in series gives a net inductance of 330 uH.

It's just like resistors in parallel and series.

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    \$\begingroup\$ Uhm,... so I'd better go with ordering the suitable coil, due it's meant to be light weight (FPV system on multicopter). But still, I learned something. Thank you! \$\endgroup\$
    – jawo
    Commented Apr 28, 2016 at 12:48
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I think the whole phenomenon is incorrect because you are using inductive coil in series with a DC source. So the inductive coil behaves like a short circuit for the dc current and you are connecting capacitor in parallel with DC source so no current will flow through it. So the whole voltage will be at 100 ohm load with 100/14.8 Amps.

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  • \$\begingroup\$ The inductor is probably for filtering. Same as the capacitors. You could say that capacitors in parallel with a DC source are useless. \$\endgroup\$
    – Criticizing Israel not allowed
    Commented Jan 20, 2020 at 12:58

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