# Kirchoff 's law in A/C

1. Jun 25, 2007

### prasanaharani

Whether Kirchoff's Law Is Applicable In A/c.then Say How?

2. Jun 25, 2007

### prasanaharani

Whether Kirchoff's Law Is Applicable In A/c.then Say How

3. Jun 25, 2007

### ice109

using impedance/reactance

$$V=I|Z|$$

where Z is

$$|Z|=\sqrt{R^2+ \chi ^2}$$

where $$\chi$$ is

$$\chi = \chi _L - \chi _C$$

where $$\chi _L$$ and $$\chi _C$$ are

$$\chi _L=2 \pi f L$$ and $$\chi _c= \frac{1}{2 \pi f C}$$

note: these equations only give you maximum or rms voltage or current

for instantaneous use these, which if you don't know, are sinusoidal functions

$$\tilde{V} = V_0e^{i(\omega t + \phi_V)}$$

and

$$\tilde{I} = I_0e^{i(\omega t + \phi_I)}$$

$$\omega = 2 \pi f$$ and $$tan( \phi ) = \frac{ \chi}{R}$$

Last edited: Jun 25, 2007
4. Jun 25, 2007

### ranger

It is very much applicable. The catch is that you should have them in complex form (phase and magnitude) and all listed currents and voltage must be of the same frequency.