# RMS math

#### richbrune

Joined Oct 28, 2005
106
I'd like to know if someone would send me the formulas for RMS voltages of various wave forms. One is a 5% duty cycle, zero to 10V positive rectangular pulse. The other is a diode "clipped" sine wave (positive portion of the sine wave only) that is 20V base to peak. I remember that I've seen a table of these formulas in years gone by, but I can't seem to find them.

Rich

#### n9352527

Joined Oct 14, 2005
1,198
Originally posted by richbrune@Nov 19 2005, 05:06 PM
I'd like to know if someone would send me the formulas for RMS voltages of various wave forms. One is a 5% duty cycle, zero to 10V positive rectangular pulse. The other is a diode "clipped" sine wave (positive portion of the sine wave only) that is 20V base to peak. I remember that I've seen a table of these formulas in years gone by, but I can't seem to find them.

Rich
[post=11752]Quoted post[/post]​
Sinusoidal Vrms=Vp/√2
Square wave (symmetrical) Vrms=Vp
Square wave (positive only, duty cycle D) Vrms=Vp*√D
Sawtooth (symmetrical) Vrms=Vp/√3
Full wave rectified sinusoidal Vrms=Vp/√2
Halfwave rectified sinusoidal Vrms=Vp/2

#### richbrune

Joined Oct 28, 2005
106
Originally posted by n9352527@Nov 19 2005, 06:06 PM
Sinusoidal Vrms=Vp/√2
Square wave (symmetrical) Vrms=Vp
Square wave (positive only, duty cycle D) Vrms=Vp*√D
Sawtooth (symmetrical) Vrms=Vp/√3
Full wave rectified sinusoidal Vrms=Vp/√2
Halfwave rectified sinusoidal Vrms=Vp/2
[post=11755]Quoted post[/post]​
So in the 10 Volt Peak, 5% duty cycle positive only pulse it would be as follows?
Vp=10
D=.05 (for 5% duty cycle)
Vrms=10*(√.05)
Vrms=10*0.22361
Vrms=2.2361

#### Firestorm

Joined Jan 24, 2005
353
Yup! 