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Inductance Equations |
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Table
1. Inductance
Equations
|
Description |
Equation |
Remarks |
|
Equivalent Inductance of Inductors in Series |
LT =
L1+L2+...+LN |
where
LT is the total inductance, L1, L2,...,LN are the N inductors in
series |
|
Equivalent Inductance of Inductors in Parallel |
1/LT =
1/L1+1/L2+...+1/LN |
where
LT is the total inductance, L1, L2,...,LN are the N inductors in
parallel |
|
Equivalent Inductance of Two Parallel Inductors |
LT = L1L2
/ (L1+L2) |
LT
equals L1 and L2 in parallel |
|
Energy
Storage in an Inductor |
E = LI2 / 2
L = 2E /
I2
I =
sqrt(2E / L) |
E =
Energy (J);
L =
Inductance (H);
I =
Current (A) |
|
Constant Charging/
Constant Discharging |
V = LI / t
I = Vt
/ L
L = Vt / I
t = LI / V |
where
L = inductance (H);
V =
voltage (V)
I =
current (A)
t =
time (s) |
|
Instantaneous Charging/
Instantaneous Discharging |
v = L
di/dt
i =
1/L ∫ vdt
|
where
L = inductance (H);
v =
voltage (V)
i =
current (A)
di =
change in current (A)
dt =
time interval (s) |
|
Inductive Reactance |
XL = 2πfL |
where
XL = inductive reactance;
L =
Inductance;
f =
frequency |
|
Mutual
Inductance |
LT = L1 +
L2 + 2M (aiding fields)
LT = L1 +
L2 - 2M (opposing fields) |
LT =
total inductance
L1,L2
= individual component self-inductances (H)
M =
mutual inductance (H) |
|
Coupling Coefficient |
k = M /
(sqrt(L1L2)) |
k =
coupling coefficient
L1,L2
= component inductances (H)
M =
mutual inductance (H) |
|
Flux
Linkage in a Coil |
L = NΦ / i |
L =
inductance (H)
N =
number of turns in the coil
Φ =
magnetic flux (Wb)
i =
instantaneous current (A) |
See Also:
Self-Inductance;
Reactance;
Various Reference Tables
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