Key For Calculations

Question 1

What is Kirchoff’s Current Law?

Answer 1

Sum I =0

I1+I2-I3-I4 etc = 0

Question 2

What is Kirchoff’s Voltage Law?

Answer 2

Sum Vloop = 0

For a closed loop:

V1-V2-V3-V4 = 0

or

Sum Vrises = Sum Vdrops

Question 3

Basic circuit rules (series and parallel) give the formulas.

Answer 3

Series: 
Zt= Z1 + Z2
It = I1 = I2
ItZt = I1*Z1 +I2*Z2
Vt = V1 + V2

Parallel: 
Zt= Z1*Z2/Z1+Z2
It = I1 + I2
Vt/Zt = V1/Z1 +V2/Z2
Vt = V1 = V2

Question 4

How to convert from complex to polar form?

Answer 4

r = X + jY

r= sqroot(X^2+Y^2)

angle = tan-1(Y/X)

Question 5

What is the cosine rule?

Answer 5

CosACosB = 0.5(Cos(A-B)+Cos(A+B))