a capacitor is frequently placed across a 110V line to reduce the noise in radios?

February 9, 2010 - 11:44 am 2 Comments

a capacitor is frequently placed across a 110V line to reduce the noise in radios.what is the smallest voltage such a capacitor should have?

110 VAC is the rms voltage that is an effective equivalent to 110VDC.

The 110 VAC voltage actually gets to a higher peak voltage of

1.414 x 110 = 155.54 volts peak

These higher peak voltages although brief in duration can damage a capacitors dielectric insulation if the peak voltage exceeds the working voltage of the cap

You could also add a safety factor of at least 10%(or more) so a cap rated no less than 175 would be required. Higher voltage rated caps (200v for example) would work and provide an added measure of safety

2 Responses to “a capacitor is frequently placed across a 110V line to reduce the noise in radios?”

  1. fatman8888 Says:

    110V. That’s the operating voltage, right? The capacitor should have a rating equal to the operating voltage.

    Is that what you were asking?
    References :

  2. Mark G Says:

    110 VAC is the rms voltage that is an effective equivalent to 110VDC.

    The 110 VAC voltage actually gets to a higher peak voltage of

    1.414 x 110 = 155.54 volts peak

    These higher peak voltages although brief in duration can damage a capacitors dielectric insulation if the peak voltage exceeds the working voltage of the cap

    You could also add a safety factor of at least 10%(or more) so a cap rated no less than 175 would be required. Higher voltage rated caps (200v for example) would work and provide an added measure of safety
    References :
    http://www.bcae1.com/voltages.htm

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