Instantaneous power:

Energy:

Average power:

Average power for a dc voltage source:

rms voltage:

rms for v � v1 � v2 � v3 � . . . :

rms current for a triangular wave:

rms current for an offset triangular wave:

rms voltage for a sine wave or a full-wave rectified sine wave: Vrms �Vm12

Irms � B aIm13b2

� I 2dc

Irms �Im13

Vrms �2V

21, rms �V

22, rms �V

23, rms � Á

Vrms � B1

T3T

0

v2(t)dt

Pdc � Vdc Iavg

P �W

T�

1

T 3t0�T

t0

p(t) dt �1

T 3t0�T

t0

v(t)i(t) dt

W � 3t2

t1

p(t)dt

p(t) � v(t)i(t)

Commonly used Powerand Converter Equations

rms voltage for a half-wave rectified sine wave:

Power factor:

Total harmonic distortion:

Distortion factor:

Buck converter:

Boost converter:

Buck-boost and Cuk converters:

SEPIC:

Flyback converter:

Forward converter: Vo � VsD aN2

N1b

Vo � Vs a D

1 � Db aN2

N1b

Vo � Vs a D

1 � Db

Vo � �Vs a D

1 � Db

Vo �Vs

1 � D

Vo � Vs D

Crest factor �Ipeak

Irms

Form factor �Irms

Iavg

DF �A1

1 � (THD)2

THD �Aa

q

n�2

I 2n

I1

pf �P

S�

P

Vrms Irms

Vrms �Vm

2