Laboratory of Basic Electronics
Exercise No 3
L, C Elements - basic applications
Student group:
Date:
Names:
Mark:
Note: Cells in tables which are in double frame should be calculated.
3.1 R,L and C measurements
Tab. 1a RLC bridge measurement.
Nominal
value
R
C1
C2
C3
C4
L
kΩ
nF
nF
nF
nF
mH
Measured
value
Tolerance [%]
x
x
Tab. 1b
R
C1
C2
L
fvar
VR
IR
ZX (R)
VC1
IC1
ZX (C1)
VC2
IC2
ZX (C2)
VL
IL
ZX (L)
kHz
V
mA
Ω
V
mA
Ω
V
mA
Ω
V
mA
Ω
1
2
4
8
10
12
15
20
Rmeas.= ..........
C1meas.= ..........
C2meas.= ..........
Lmeas.= ..........
- set amplitude on function generator HM8130 VL=1Vpp
C1nom=..........
C2nom=..........
Lnom=..........
Rnom= ...........
(reading from an element)
3.2 Transmission measurements
Tab. 2.1 High and low-pass filter, R=1.2kΩ, C= .......
fvar
Hz 20 100 500 1
5
10 20 30 45 60 120 300 500
kHz kHz kHz kHz kHz kHz kHz kHz kHz kHz
Vin1
V
Vout1
V
Vin2
V
Vout2
V
Vout1/ Vin1 dB
Vout2/ Vin2 dB
Tab. 2.2 Bandpass filter, R=600Ω, L=10mH, C=var (10nF and 47nF)
kHz 0.02 0.2
1
5
6
7
9
11 12
fvar
Vin1
V
Vout1 -C=10nF V
Vin2
V
Vout2 -C=47nF V
Vout1/ Vin1 dB
Vout2/ Vin2 dB
Tab. 2.3 Notch filter, R=var (200 Ω and 600 Ω), C=10nF, L=10mH
kHz 2
8
10 11 12
16 18
fvar
Vin1
V
Vout1 - R=200Ω V
Vin2
V
Vout2 - R=600Ω V
Vout1/ Vin1
dB
Vout2/ Vin2
dB
14
20
16
25
25
40
60 150 400
60
- find resonant frequency by determining maximum output voltage respectively Vout1
and Vout2
Measurement data evaluation
Complete the tables and:
1. Calculate the tolerance of elements for value in Table 1a, following the formula:
NV − MV
where NV - nominal value,
tolerance =
⋅100% ,
NV
MV - measured value.
2. Plot ZX for resistance, capacitances and inductance versus frequency for data in Table 1b in
the linear scale.
3. Calculate the mean measurement value of the elements for values in Table 1b, following
the formula:
∑ Ri
,
where n - number of measurements,
Rmeas = n
n
Ri - measured value for i frequency.
1
Cmeas =
∑ω Z
n
i
n
i
,
where n - number of measurements,
Zi - measured value for i frequency.
Zi
Lmeas =
∑ω
n
n
i
,
where n - number of measurements,
Zi - measured value for i frequency.
4. Plot
Vout
= f ( frequency ) in point 3.2.1, X axe should be logarithmic scale and Y axe
Vin
should be in dB scale -
V 
Vout
[dB] = 20 log out  . Determine and mark f3dB.
Vin
 Vin 
Vout
= f ( frequency ) in point 3.2.2, X axe should be logarithmic scale and Y axe
Vin
should be in dB scale. Determine and mark f0 , ∆f3dB , Q. Calculate theoretical values of
f0 , Q and mark them.
5. Plot
Vout
= f ( frequency ) in point 3.2.3, X axe should be logarithmic scale and Y axe
Vin
should be in dB scale. Determine and mark f0 , ∆f3dB , Q. Calculate theoretical values of
f0 , Q and mark them.
6. Plot
7. Comment on the results.