  # Basic Electronics Formulas of Electronics Component

BASIC ELECTRIC CIRCUITS
OHM'S LAW KIRCHOFF'S LAWS

The sum of the voltage drops around a series circuit equals the applied voltage E(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 Connected

R(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 (watt-seconds)
C = the capacitance in farads
E = the applied voltage in volts
Paralel Connected

C(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 = RC
Theoritically 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 connected

L(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
Inductive Xl = Reactance in Ohms
f = frequency in Hertz
L = in Henry
RESONANCE   F = Resonant frequency in HertzL = inductance in HenryC = Capacitance in Farad

## Links

• Electrical Circuit THeorems
• Electrical Formulas
• Basic electrical laws and circuits analysis & circuits theory
• BASIC ELECTRONICS

Updated January, 2004 