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I have an RC snubber that is in parallel to a DC motor that runs forward and reverse.

Is this snubber going to work differently in the forward direction than it does in the reverse direction? Does the resistor/capacitor orientation matter with respect to applied voltage?

RC Snubber

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    \$\begingroup\$ No, your circuit is bipolar in this regard. Flipping the R and C makes no difference. \$\endgroup\$
    – winny
    Apr 6, 2021 at 19:19

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An RC snubber is perfectly linear, you only have resistors and non-polarized (usually film or ceramic) capacitors. So it work exactly in the same way both in the forward and in the reverse direction.

The other common encountered snubber (the RCD) is not, since it has a diode: like this, it's used for dampening inductive switches but it's optimized since the spike is only in one direction. That won't work in a bidirectional brushed motor.

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As long as the capacitors are not polarized (and generally capacitors << 1 μF are not polarized), electrically the arrangement of R & C in series doesn't matter. Therefore the snubber will work identically in either polarity of motor drive.

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  • \$\begingroup\$ Tantalum caps are polarized. I don't see them too often nowadays, but just thought I would mention it. Why did you choose to answer this old question? \$\endgroup\$
    – user57037
    Aug 11, 2022 at 7:31

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