BASIC ELECTRIC CIRCUITS 
OHM'S LAW
 KIRCHOFF'S LAWS
The sum of the voltage drops around a series circuit equals the applied voltageE(applied)=E1+E2+....En The current flowing toward a point in a circuit must equal the current flowing away from that point I(in)=I(out)1+I(out)2+...I(out)n

Unknown Value  Formula 
E  
I  
P  
R  
E = voltage in volts I = the current in amperes P = the power expressed in watts R = the risistance in ohms

Resistance Circuit 
Series ConnectedR(tot) = R1 + R2 + . . . Rn Paralel Connected  2 Paralel Connected Resistor 
Capacitance Circuit 
Paralel Plates
A = in square centimeter d = in centimeter K = dielectrict constant between the plates Charge Stored Q = CE
Q = the charge in coulumbs C = the capacitance in farads E = the voltage impressed across the capacitor Energy Stored
W = the energy in joules (wattseconds) C = the capacitance in farads E = the applied voltage in volts  Paralel ConnectedC(tot) = C1 + C2 + ....Cn Series Connected 2 Series Connected The voltage across each capacitor connected in series is proportional to the total capacitance divided by the capacitance of the capacitor 
RC Time Constant 
E(t) = Capacitor EMF in volts at t E(s) = potential of charging batteries in volts t = time in seconds e = natural logarithmic base = 2.718 R = resistance in ohm C = Capacitance in farads  T = RCTheoritically charging time is never finished, for mathimatical reasons the above formula is taken, based on the capacitor voltage increases/decreases up to/by 63 % of the applied/initial voltage T = time constant in seconds C = capacitance in farads R = resistance in ohm 
Inductance Circuit 
Series connectedL(tot) = L1 + L2 + . . .Ln Paralel Connected  2 Paralel Connected Inductors 
Mutual Inductance of 2 coils:M = mutual inductance expressed in the same unit as La and Lb La is the total inductance of l1 and l2 with fields aiding Lb = the total inductance of L1 and L1 with field opposing  Coupling coeficient: K = coupling coeficient M = mutual inductance L1 L2 inductance 
Reactance 
Capacitive
Xc= Reactance in Ohms f = frequency in Hertz C= in Farad  InductiveXl = Reactance in Ohms f = frequency in Hertz L = in Henry 
RESONANCE  F = Resonant frequency in Hertz L = inductance in Henry C = Capacitance in Farad 
