# What is the RMS reverse voltage for diodes?

in The datasheet

1N4001 Vr RMS 35V
1N4007 Vr RMS 700V


What is the meaning of RMS reverse voltage?

• Please add a link to the datasheet where you found it. – jippie Jun 8 '13 at 16:03

Clabbachio is correct for a sinewave and that is how the datasheet specifies the voltages. It is the peak voltage that should never be exceeded as this will breakdown the diode junction.

Other voltage waveforms will have different values for peak and rms. (for example in a power converter where signals are switch pulses.) The r.m.s. value can be quite low compared to the peak voltage.

In these cases the diode must be chosen to withstand the peak reverse voltage.

If you look at the datasheet, you can see that two reverse voltages are specified, a peak and an RMS voltage: both refer to an AC voltage at 60 Hz, the most likely condition in which the diode has a reverse voltage applied.

Since we're talking AC, the RMS (Root Mean Square) voltage is the equivalent DC voltage of the AC signal, in terms of active power. If you look at the values, the indicated RMS voltage is equal to the peak voltage divided by the square root of 2.

Therefore a $35 \text{ V}_\text{RMS}$ AC signal will have 50 volts peak, which will burn the 4001.

## protected by clabacchio♦Jun 8 '13 at 16:18

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