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Electric current
Electric current
9 formulas · Physics
Electric current
I
=
q
t
I=\dfrac{q}{t}
I
=
t
q
Ohm's law
I
=
U
R
I=\dfrac{U}{R}
I
=
R
U
Resistance of a conductor
R
=
ρ
l
S
R=\rho\dfrac{l}{S}
R
=
ρ
S
l
Electric power
P
=
U
I
=
I
2
R
=
U
2
R
P=UI=I^2R=\dfrac{U^2}{R}
P
=
U
I
=
I
2
R
=
R
U
2
Work of electric current (energy)
W
=
U
I
t
W=UIt
W
=
U
I
t
Equivalent resistance — series
R
=
R
1
+
R
2
+
…
R=R_1+R_2+\dots
R
=
R
1
+
R
2
+
…
Equivalent resistance — parallel
1
R
=
1
R
1
+
1
R
2
+
…
\dfrac{1}{R}=\dfrac{1}{R_1}+\dfrac{1}{R_2}+\dots
R
1
=
R
1
1
+
R
2
1
+
…
Terminal voltage and internal resistance
U
=
ε
−
I
r
U=\varepsilon-Ir
U
=
ε
−
I
r
Joule heating
Q
=
I
2
R
t
Q=I^2Rt
Q
=
I
2
R
t
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