3B SCIENTIFIC PHYSICS U188501 Instrucciones De Uso página 7

At the ideal setting, slight flickering of the LED may
be observed. If the LED lights up brightly, the signal
is overloaded.
•
Note down the resonance voltage of the coil U
and the corresponding resonant frequency ν
(see Fig. 6).
•
If an oscilloscope is used the resonance voltage
can be read directly from the scope screen.
•
If 3B NETlog™ is being used, exit oscilloscope
mode and save the results. TH table of meas-
urements displayed can be displayed graphically
by clicking the appropriate button and the peak
can then be marked by means of the cursor. The
resonance voltage for the coil U
played.
•
Repeat the measurement for various frequencies
(in 5 MHz-steps).
R
R
is then dis-
R
Fig. 5 ESR experiment set-up using an oscilloscope
3
3.5 Evaluation
•
Calculate the magnetic field according to the
following equation:
mT
= ⋅
B . 3 47 U
R R
V
•
Plot a graph of magnetic field against frequency.
(see Fig. 8)
The relationship between the resonant frequency ν
and the magnetic field at resonance B
μ
ν ⋅ ⋅
B
= g B
R
R
h
where
J
−
μ = ⋅
24
. 9 28 10
B
T
−
= ⋅
34
h . 6 626 10 Js
For electrons in free space the Landé factor g = 2.002
R
is as follows:
R