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ELECTRIC AND DIRECT CURRENT CIRCUIT - Coggle Diagram
ELECTRIC AND DIRECT CURRENT CIRCUIT
Electric Current
Electric Current : the flow of electric charge from one place to another
Electric Current, I = Q/t
SI unit, Coulomb per second = Ampere (A)
Electric Circuit : A closed path through which charge can flow, returning to its starting point
Direct-Current Circuits
Electromotive force,
emf
A battery that is disconnected from any circuit has an electric potential difference between its terminals
ε = V + Ir
ε = the terminal voltage when current is zero (open circuit voltage)
ϵ = I(r+R)
in terms of internal resistance
Resistance and Ohm's Law
Ohm's Law , V = IR
SI Unit : volt,V
Two wires of the same length and diameter will have different resistances if they are made of different materials. This property of material called resisitivity.
R = ρL/A
Energy and Power in Electric Circuits
P = IV
SI Unit : Watt, W
Series and Parallel Circuit
SERIES
Current : Itotal = I1 = I2 = I3
Voltage : Vtotal = V1 + V2 + V3
Resistance: Rtotal = R1 + R2 + R3
PARALLEL
Current : Itotal = I1 + I2 + I3
Voltage : Vtotal = V1 = V2 = V3
Resistance : 1/Rtotal = 1/R1 + 1/R2 + 1/R3
Kirchhoff's Rules
Junction Rule
Consequence of
charge
conservation
Loop Rule
Consequence of
energy
conservation
Ist Law Kirchhoff's
ΣI(in) = Σ I (out)
2nd Law Kirchhoff's
Σϵ = ΣIR
Circuit Containing Capacitors
SERIES
1/Ctotal = 1/C1 + 1/C2 + 1/C3
Charge
across capacitor is the
same
and equal to the total charge in the series circuit
PARALLEL
C total = C1 + C2 + C3
Voltage
across each capacitor is the
same
and equal to the voltage in parallel circuit
RC Circuit
Charging Process
Q = Q0 (1- e ^ (-t/RC))
V = V0 (1-e^(-t/RC))
I = I0(e^-t/RC)
Discharging Process
Q = Q0 e^-t/RC
V = V0 e^-t/RC
I = I0 e^-t/RC
