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1) Current
WHERE :
I = CURRENT
Q = Charges
t = Time
NOTE: Current is proportional to rate of charges
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V = I R
WHERE :
V = VOLTAGE DROP
I = CURRENT
R = RESISTANCE
CONSTANTS: Temperature and other Physical factors
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3) Drift Velocity
WHERE :
V = Drift Velocity
L = Length
t = Time
NOTE: Velocity of electrons flowing in conductor
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4) Current Density
WHERE :
J = Current Density
I = Current
A = Area
NOTE: Flowing current through conductor in unit of area
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5) Combination of current and drift velocity
WHERE :
V = Drift Velocity
n = Number of Electrons
e = Charge of an electron
I = Current
A = Area
NOTE: In this case the length of the conductor is taken as “L” and the area of the conductor is taken as “A”. After that it is substituted for Drift velocity Equation.
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6) Resistance
WHERE :
R = Resistance
℘ = Resistivity
L = Length of Conductor
A = Area
NOTE: Resistance depends on the Resistivity of the conductor, the cross sectional area of the conductor and its length.
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7) Temperature coefficient of resistance
WHERE :
R(0 )= Zero temperature Resistance
R(ᶿ )= teta temperature Resistance
α = Temperature coefficient
e = Temperature
NOTE: Resistance increases as temperature increases.
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8) Series Resistance
WHERE :
R total= Total resistance
NOTE: The total resistance of a series resistance system is equal to the sum of the resistance. There is a potential division here
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9) Parallel Resistance
WHERE :
1/R total= Total resistance
NOTE: The total resistance of a Parallel resistance system is equal to the sum of the 1/(resistance). There is a current division here.
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10) Potential difference of Cell
WHERE :
V(a ) - V(b )= Voltage difference
E = Electromagnetic force
I = Current
r = Internal Resistance
IMPORTANT: When the current flows out of the cell is "-Ir" and "+ Ir" is the current flows into the cell.
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11) Series Cell
WHERE :
E(total) = Total Electromagnetic force
r(total) = Total Internal Resistance
IMPORTANT: When installing the cell must focus for the polarity.
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12) Parallel Cell
WHERE :
E(total)/r(total) = Total Electromagnetic force
r(total) = Total Internal Resistance
IMPORTANT: When the cells are in parallel, they must first find the internal resistance and then calculate the electromagnetic force.
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13) Kirchhoff`s Current law
WHERE :
I(1) and I(2) = Coming Currents
I(3) and I(4)+... = Going away Currents
IMPORTANT: The sum of the electric currents coming to a junction in an electrical circuit is equal to the sum of the electric currents coming out of that junction.
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14) Kirchhoff`s Voltage law
∑ E = ∑ (IR)
WHERE :
E = Electromagnetic force
IR = Potential difference
Є(sigma) = Sum
IMPORTANT: The sum of the electromagnetic forces along a selected cyclic direction of a closed circuit is equal to the sum of the potential difference.
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15) Electrical Energy
WHERE :
w = Electrical energy
V = Potential difference
I = Current
R = Resistance
t = Time
NOTE: Electrical energy is measured in joules (J). The above equations are derived by substituting "V = I R" into "W = V I t".
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16) Electrical Power
WHERE :
P = Electrical Power
V = Potential difference
I = Current
R = Resistance
NOTE: Electrical energy is measured in watts (W).The above equations are derived by substituting "V = I R" into "P = V I ".
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17) Relationship of Thermal Energy and Electrical Energy
WHERE :
Q = Thermal Energy
V = Potential difference
I = Current
R = Resistance
t = Time
NOTE: Electric energy can also be converted to thermal energy.
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18) Electrical Energy of Cell
W = E I t
WHERE :
W = Electrical Energy
E = Electromagnetic force
I = Current
t = Time
NOTE: The internal chemical energy of a cell is converted to electrical energy.
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