Vectronics SWR-66 - Manual (Page 4)

SWR-66 Dip Meter Adapter Owner's Manual
4
Measure coefficient of coupling of two resonant circuits.
1. Measure the resonant frequency at one coil (refer to the SWR-584 owner's manual) and
record it as Fs . This is a measurement of the resonant frequency of both circuits in their
coupled state.
2. Make a open in the other tank circuit. Remeasure the resonant frequency and it record as
Fo. This is a measurement of the resonant frequency of just one uncoupled tank circuit.
3. Now solve the equation below for the coefficient of coupling, k. The coefficient of
coupling is a value between 0 and 100. If two coils are tightly coupled they will have a
high k, 100 being perfect. Loosely coupled coils have a low k.
k = 1-
Ls
Lo
Measure coefficient of coupling of loosely coupled coils.
1. Measure the inductance of one coil (refer to the SWR-584 owner's manual) and record it
as L. This is a measurement of the inductance of one inductor coupled to the other coil.
2. Make a short across the other inductor. Remeasure and record the inductance as Ls. This
is a measurement of the resonant frequency of just one uncoupled inductor.
3. Now solve the equation below for the coefficient of coupling, k. The coefficient of
coupling is a value between 0 and 100. If two coils are tightly coupled they will have a
high k, 100 being perfect. Loosely coupled coils have a low k.
k =.5 1-
L
Ls
F
H
G I
K
J
Measure mutual inductance for two loosely coupled coils.
1. Measure the inductance of both coils in series (refer to the SWR-584 owner's manual).
Record this value as L1.
2. Reverse one coil and measure the inductance of both coils in series. Record this value as
L2. You have measured the resonance of the coils in and out of phase.
3. Solve this equations with the values you have recorded.
M =.5 k L1 L2