Electronics 1 (FYSE301 + FYSE302)
Laboratory works of course Electronics 1 involve two labs. The first lab is included in part A
(FYSE301) and the second in part B (FYSE302). If doing part A only, you’ll have to do only the work
1. The ones who do the whole course have to do both labs 1 and 2. The labs are described in following:
Lab 1:
FYSE301
Part A
Basic components: resistor, diode and field effect transistor (FET). The use of a resistor
as part of a circuit is studied, characteristic curves are measured for diodes,
limiting/clipping circuit is built using diodes, build a basic biasing circuit for a FET
and measure its characteristic curves.
Lab 2:
FYSE302
Part B
Characteristic curves are measured for zener diodes and it is used to regulate a voltage.
Characteristics are measured for bipolar transistor and properties of a common emitter
transistor amplifier are studied.
Instructions include:
- Pre-exercises, which should be done before starting the measurements (E)
- Measurements to be done (M)
- Analysis to be done using the results of the measurements (T)
To take account during measurements:
• All connections are made to a special board (bimboard) unless notes otherwise.
The connections at the side of the board (V1-3 ja ”ground”) are NOT connected to anywhere in
advance. Thus, if using those, one should connect them to the desired point in the circuit using
separate wires. Bimboard consists of three similar but separate pieces: the whole row A is at the
same potential. Below this row there are columns (1-47), which are connected so that in each
column the rows B-F and similarly rows G-K are at the same potential. Under all of these there is
row L, which is similar to row A.
A
10
V1
V2
15
45
B
C
D
E
G
H
I
J
K
L
A
• Try to build as simple circuits as possible, i.e., minimize the number of wires. Also, there is no
advantage of using too long cables.
• The necessary meters/gauges are not market on the circuit diagrams, but only the values to be
measured are told. Measurements are done either by oscilloscope (one can see the shape the voltage
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signal) or multimeter (easier to read). One can/should also partly decide himself the ranges and
quantities to be measured. Voltages are always measured as compared to ground.
NB. Voltage is measured using – and + connectors (NOT between the ground and +)
• Is the circuit is not operating as desired, check all the connections and settings of components /
voltage sources used. After this repeat the measurement and the checking, again. If the reason for
malfunction is still not found, try if changing of some of the components has any affect (to find out
probably broken components).
• MAXCOM-9300 includes an adjustable DC voltage source (also some non-adjustable), function
generator and multimeter. The GW, which is situated at the panel above the table, is used as a
second adjustable DC voltage source.
• All the components needed in measurements are found in the pigeonholes at the laboratory. This
should hold also after your work!! Just in case always check the values of the resistors used!!
• Remember: Current meter always in series and voltage meter always parallel with the component
being measured. RCurrentmeter ≈ 0 ja RVoltagemeter ≈ ∞
V
Z
A
Z
Instructions for the reports are same as for the cum laude –laboratory works in general (found at www
pages of the student laboratory). Common sense is allowed (sometimes even desirable) in applying of
error analysis, i.e., derivation of the formulas for error propagation is not necessary. On the report, one
should always compare the measured result to the specifications announced by the manufacturer if it is
possible (e.g.zener voltages). There is a folder at the laboratory where the data sheets of most of the
components are collected, but one can easily find them also at the web pages of the manufacturer along
the product code of the component. Also include the answers to the pre-exercises to the report. Two of
the works are evaluated using grades 1-5 and two with grades passed/discarded.
One might find following books helpful, when doing the measurements and the report:
• R.J Smith: Electronics Circuit & Devices
• Horenstein, Wassermann: Microelectronic circuit and devices (at the laboratory)
• V. Volotinen: Analogiaelektroniikka (at the laboratory)(in finnish)
Www-addresses of some of the common manufacturers:
www.st.com
www.nsc.com
www.harris.com
www.motorola.com
www.siemens.com
www.philips.com
www.fairchildsemi.com
www.ti.com
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Lab 1:
E1.1
FYSE301
Add a load RL to the circuit shown in Fig. 1.1. Also, add a current meter so that you can
measure the current through the resistor R2.
R1
+
R2
V1
V out
V2
+
Fig 1.1: Circuit of resistors
E1.2
Familiarize yourself with the characteristics of a general diode. Find out the maximum reverse
voltages (VR and VRRM) and the maximum forward currents (IF and IFRM) for a diode BAS216
using the data sheets. What is the difference between the two different maximum values? For
which purposes this diode is designed?
E1.3
What type of transistor is BS170? Find out the order of pins in TO-92 packing (G,D,S). Find
out the maximum allowed continuous gate voltage VGS and current IDS.
E1.4
Explain what is meant by the saturation area in the case of FET. How is the component
operating within this area and outside of this area?
1.1 Current dividing and superposition theorem
Build a circuit of E1.1 (with your additions), where R1 = 390 Ω , R2 = 680 Ω and RL = 560 Ω.
M1.1
Measure the current through R2 in following cases:
1. V1 is shorted (V1 = 0) and V2 = 5 V
2. V2 is shorted and V1 = 10 V
3. V1 = 10 V and V2 = 5 V
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1.2 Voltage dividing, Thévenin’s theorem
Modify your circuit along Fig. 1.2. Replace resistor RL with potentiometer (100kΩ).
M1.2
Measure the voltage Vo across R2 as a function of current Io (by changing the potentiometer
from one end to another), when V1 = 10 V.
Æ I0
R1
+
R2
V1
V0
RL
Figure 1.2: Circuit for voltage dividing
1.3 Measuring the diode characteristics
M1.3
Measure the IV-characteristics, Vd = f (Id), of a diode 1N4007 with reverse and forward biasing
using a circuit shown in Fig. 1.3.
Increase the voltage VS step by step starting from zero and read the current Id corresponding to each
value of the voltage Vd. Current Id can be measured as a voltage across the resistor R = 100 Ω. Use GW
DC voltage source and its fine tune. Reverse biased case can be measured easiest by swapping the
outputs of the voltage source. Don’t exceed the maximum power handling capacity of the resistor (P =
U⋅ I = ¼ W)!
VS
R
VR
Vd
Figure 1.3: Circuit for measuring diode characteristics.
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1.4 Clippers
Use still a diode 1N4007 but now use 2k2 (2.2kΩ) resistor. Using these build a series clipper along
what shown in Fig. 1.4a). Take the input voltage from the function generator (maxcom output connector 50Ω/600Ω) and adjust it so that peak-to-peak value (Vp-p) for a sinusoidal signal is 20 V and
the frequency is ~1 kHz.
M1.4
Measure the output voltage (vout) using an oscilloscope. Draw the input and output voltages to
same graph.
M1.5
What happens if the frequency is increased, and why? Draw the waveform of the output
voltage, when f ≈ 15 kHz.
Add a DC voltage source to the circuit (frequency again ~1kHz).
M1.6
Try the effect of the DC voltage to the output signal. Draw the input and output voltages to the
same graph, when V1 = 5V.
+
V1
V in
v in
V out
(a)
vout
(b)
Figure 1.4: Serial clippers
Change the circuit to the parallel clipper (Fig. 1.5 a). Use the same components and measurement
setups.
V in
V out
V in
V out
V2
(a)
+
(b)
Figure 1.5: Parallel clippers
M1.7
Measure (= draw) the input and output voltages for both parallel clippers (a and b), when V2 =
5V. NB: The direction of the diode is changed at b!
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1.5 Measurement of the characteristic curves for a Field Effect Transistor (FET)
Gate voltage VGS is applied to FET’s gate G from a voltage source VG. Due to the voltage dividing only
a part of the voltage VG is actually applied to the gate (This prevents too large gate voltages, which
could break the FET). The Drain-Source voltage across the transistor, VDS, can be approximated to be
the same as the operating voltage VD, since the voltage drop across the resistor R1 is negligible. Build a
circuit along the diagram in figure 1.6. Now R1 = 10 Ω, R2 = 1 kΩ, R3 = 20 kΩ and R4 = 100 kΩ.
VG
VD
ID
R4
R1
D
R2
G
R3
S
VGS
Figure 1.6: Circuit to measure the characteristic curves for a FET.
Initial tunings:
- Set the trimmer R3 in an “up” position so that the VGS is at the maximum: VGS,max ≈ [R3/(R3+R4)]*VG .
- Adjust the voltage VD to 15 Volts.
- Increase VG slowly until the Drain current ID is at its maximum of 20 mA.
- Decrease the voltage VD to zero.
Now you have adjusted the maximum gate voltage allowed. After this only adjust the gate voltage by
the trimmer R3.
M1.8
Measure characteristic (VDS, ID) –curves with five different values of VGS. You can choose the
values.
Suitable values for VGS can be found between 1.5 V and 3V depending on the voltage with which the
FET starts to conduct. For every curve, measure ID with the same values of VDS: 1V, 5V, 10V and 15V.
The current ID can be measured as a voltage across the resistor R1.
With high currents the FET starts to heat up, so decrease the operating voltage VD to zero immediately
after each measurement. Use the cooling system, if needed (Heatsink that can be put on the top of the
FET).
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Current dividing and ja superposition theorem
T1.1
T1.2
Derive the formula for a current I2 flowing through the resistor R2 (M1.1).
Compare the values measured for I2 (M1.1) to the calculated ones.
Voltage dividing, Thévenin’s theorem
T1.3
T1.4
T1.5
Draw the measured load line.
Draw a Thévenin’s equivalent circuit as seen by the load resistance RL. Values for Vth and Rth
are calculated using the values of R1, R2 and V1.
Compare the calculated values to the values obtained for Vth and Rth via measurements. Explain
how Vth and Rth can be determined from a measured graph.
Measuring the diode characteristics
T1.6
T1.7
Using measured results, draw the IV-characteristics for a diode and determine the point of
operation if the voltage is chosen to be +3V.
Use the graph of IV-characteristics to determine the dynamic resistance of the diode when Id is
around 8 mA. Dynamic resistance is determined by the slope of the IV-curve at the chosen
operating point (Id = 8 mA).
Clippers
T1.8
T1.9
Conclude along the obtained graph how the output voltage of the serial clipper (circuit b) is
changed if the polarity of the input voltage is changed. Draw a graph.
Conclude along the obtained graph how the output voltage of the parallel clipper (circuit b) is
changed if the polarity (direction) of the diode is changed. Draw a graph.
Measurement of the characteristic curves for a FET
T1.10
T1.11
Draw the (VDS, ID) -curves with the voltages VGS you chose.
Determine from the curves obtained above, the transconductance gm and the output impedance
rd of the FET.
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Lab 2:
FYSE302
E2.1
Find out from the data sheets a zener voltage, maximum tolerance of the voltage, maximum
power loss, maximum zener current and type of the package for a zener diode BZX79C5V1.
E2.2
Explain how the regulation of the input and the load/output voltages works, if realized by using
a zener diode as in a circuit shown in Fig. 2.2.
E2.3
Find out the order of pins in transistor 2N2222 (TO-18). What is the maximum allowed
collector-emitter voltage and current?
E2.4
Familiarize youself with the characteristic curves of the transistor. What is meant by cutoff-,
saturation- and linear range in the case of bipolar transistor? What is the saturation range in the
case of FET? How are the both types working on the different ranges?
E2.5
What is the function of the resistors R1, R2, RE and RC in the circuit shown in Fig. 2.3? What is
the benefit (for the circuit) obtained by using the capacitances C1 and C2? How about the
capacitance CE?
2.1
Measuring the characteristic curves of a Zener diode
Build a circuit shown in Fig. 2.1, where the zener diode is of the type BZX79C5V1 and the resistance R
is 100Ω.
M2.1
Measure the IV-characteristics VZ (IZ) of the reverse biased zener diode.
Use GW voltage source and its fine tune. Increase the voltage V step by step starting from zero and
read the current IZ corresponding to each value of the voltage VZ. Current IZ can be measured as a
voltage VX across the resistor. Measure precisely (enough points) the area around zener voltage, i.e., the
quick rise in current.
V = 0 …7 V
Turn the zener diode BZX79C5V1 around to apply
forward bias.
M2.2
VR
Measure the forward voltage when the
current is 10 mA (Only one value, which
is then compared to the similar value
measured from a regular diode).
VZ
Figure 2.1: Circuit for measuring
characteristics of a zener diode.
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2.2 Voltage regulation using a zener diode
The most common application of zener diode is a voltage regulation. If using a DC voltage source the
purpose of the regulator is to keep the output voltage constant regardless of the changes at the output
current and in input voltage. Build a typical parallel regulator circuit utilizing a zener diode as shown in
Fig. 2.2. Zener diode is reverse biased along the input voltage VS. Use the following components: RL =
330R, RS = 220R and zener diode of a type BZX79C5V1.
RS
VS
RL
V out
Figure 2.2: Simple voltage regulator.
M2.3
Using a current meter, measure the current IZ through the reverse biased zener diode as a
function of the voltage across the diode (VZ = Vout), while increasing the DC voltage VS from 0
to 12 V. Take more points around the zener voltage.
Set the input voltage to 10 V.
M2.4
Use a 10k potentiometer as a load resistor. Measure the output voltage Vout and load current IL,
as a function of the load resistance (RL ≈ 0– 10 kΩ).
2.2 Measurement of the characteristic curves for a bipolar transistor
Task is to measure the characteristic output curves IC(VCE) for an npn bipolar transistor of a type
2N2222 using a circuit shown in figure 2.3.
RC
10 R
100 k
VC C
IC
1k
VBB
IB
Figure 2.3: Circuit for the measurement of the characteristic curves of a bipolar transistor.
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Connect the positive operating voltage VCC to the transistor. Since the voltage drop in the resistor RC is
small (negligible) one can assume the voltage across the transistor, VCE, to be the same as the operating
voltage VCC. By the voltage source VBB one can adjust the base current IB. The base current, IB, and the
collector current, IC, can be measured by multimeter across the resistance 1 kΩ and 10 Ω, respectively.
M2.5
Measure the (VCE , IC) –points with five different values of IB (IB = 5 - 50 μA) chosen by you.
Measurement in practice:
- Adjust the base current, IB, to the first chosen value and measure both VCE and IC while varying the
operating voltage VCC (~VCE). In other words, measure (VCE, IC)–points.
- Change the value of IB and repeat the measurement.
- With every value of IB use the same voltages in VCC (~VCE) (for example. 3, 5, 10, 15 and 20 V).
- Perform the measurements promtly and turn VCE down immediately, after measuring one series of
the (VCE, IC)–points. Large current might heat the transistor and thus distort the measured results.
2.4 Common emitter amplifier
Common emitter circuitry is the most usual way to realize a transistor amplifier. In our case the
amplifier is for small voltages (vin = 0,001…5 V) and it can be operated on the frequency range of 30
Hz-1MHz.
There exists a ready-made circuit board with circuitry for common emitter amplifier already built in
as shown in figure 2.4. Use the same transistor as in the previous measurements.
VCC
R1
IC
RC
V
C
RX
C1
vout
V
C2
B
vin
+
V
E
vS
RY
R2
RE
CE
Figure 2.4: Common emitter amplifier
Find out the values of the used resistors by the color coding (You can naturally double check by
measuring them).
M2.6
Connect the operating voltage (VCC) +20V and measure the voltages VB ,VE and VC as well as
the idle current IQC, when vS = 0 V. The current IQC can be measured as a voltage across the
resistor RC.
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Connect a 1 kΩ load resistor RL to the output and feed the input (vin) with a sine wave taken from a
signal generator. The sine wave, vS, amplitude should be 60 mVP-P. (If needed, add the resistors RX =
100 Ω and RY = 10Ω.)
M2.7
Measure the input vin and the output voltages vout by the oscilloscope as a function of
frequency. [NB. Start with a low enough frequency and measure the voltage vin, NOT vS !!]
After this, take away the shorting capacitance of the emitter resistor CE = 470 μF.
M2.8
Measure the output voltage vout by the oscilloscope as a function of frequency. How did the
amplification change (f = 10 kHz) if compared to M2.7?
The input and output resistances of the amplifier can be measured by utilizing an adjustable resistor.
Use high enough frequency on the input (> 2 kHz), so that the amplification is at its maximum.
M2.9
Measurement of the output resistance Ro (reconnect the capacitance CE).
- Measure the output voltage, vout, first without the load (RL = ∞).
- Connect the potentiometer (10k0) as a load RL to the output
- Adjust the value of RL so that the output voltage, vout, has decreased to one half of the max.
Now the value of RL is the same as Ro.
Change a potentiometer in the place of the resistor RX and take the resistor RY totally away (figure 2.5).
Connect the load resistor RL (=1k0) to the output.
RX
+
v1
v2
C1
VS
Figure 2.5: Measurement of the input resistance
M2.10 Measurement of the input resistance Ri. Measure a voltage from the both ends of the
potentiometer RX and adjust RX so that v2 is one half of the v1. Now the value of RX is the same
as Ri.
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Measuring the characteristics curves of a Zener diode
T2.1 Draw the VI-characteristics for the Zener diode VZ(IZ), i.e., the voltage as a function of the
current to the same graph. What is the measured zener voltage?
T2.2 Use the graph of VI-characteristics to determine the dynamic resistance of the diode at the linear
part of the curve, i.e., voltages over the zener voltage.
T2.3 Draw the reverse and forward biased VI-curves on the same image. Compare the sharpness of
the transition near the forward biased threshold and reverse biased Zener voltage.
Voltage regulation using a zener diode
T2.4 Draw a regulation graph for the output voltage Vout (VS) and determine the input voltage VS
after which the zener diode start to regulate. Is this voltage same as the zener voltage of the
diode?
T2.5 When the zener diode is conducting, what happens to the current IZ through it if the input
voltage VS is further increased?
T2.6 Determine (by calculating) the range within which the input voltage is allowed to vary to still
keep the output voltage constant at the circuit of Fig. 2.2. The zener current should not go
below 5 mA (since then the regulation is not working efficiently), neither the power
consumption of zener diode should not exceed 500 mW. What would be the power
consumption in front resistor if using this input voltage? The dynamic resistance of the zener
diode is assumed to be zero.
T2.7 Draw the regulation graph for the load VL (IL).
T2.8 What is the maximum load current one can get out from the circuit so that regulation is still
working? What limits the load current?
T2.9 Determine (by calculating) the range within which the load resistance is allowed to vary to still
keep the output voltage at the nominal value of 5.1 V and not to break the zener diode (values
for the components are the same as in 2.2). The operating voltage is constant VS = 30 V. The
zener current should not go below 5 mA and the dynamic resistance of the zener diode is
assumed to be zero.
Voltage regulation is usually done with special regulators, e.g., LM140 /340 /7800
T2.10
Using the data sheets of the manufacturers, find out typical properties for regulators. How
regulators are classified and what kind of information can be obtained from their product
codes?
Measurement of the characteristic curves for a bipolar transistor
T2.11 Draw the characteristic curves measured
T2.12 Draw the transport curves IC (IB) for three different values of VCE used (e.g. 3, 5 and 10 V)
T2.13 Use the characteristic curves drawn above to determine the static amplification of the used
transistor hFE (= β ) at the point where the collector current is 10 mA and collector-emitter
voltage is 10 V. Compare the result achieved to the dc-current amplification hFE found on the
data sheet.
T2.14 Can the other h-parameters (hie , hoe and hre) be determined from the drawn characteristic
curves? How?
T2.15 The characteristic curves of bipolar transistor and FETs look pretty much similar. However,
there is a big difference in operation of these types of semiconductor components. What is
that?
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Common emitter amplifier
T2.16 Calculate the theoretical values for VB ,VE and VC as well as for the idle current IQC. Solve the
value of the base current IB (e.g. by loop current method). Use the β-value determined before.
T2.17 Draw the dc- and ac- load lines to the same image as the previously measured characteristic
curves, assuming the operation voltage of +20V.
T2.18 Draw the measured frequency response on the logarithmic scale and determine –3dB –points
of the amplifier from it (low and high frequency limits). How big is the ac-amplification for
the circuit?
T2.19 Calculate the theoretical values for voltage (Av) and current amplification (Ai), when
Av =
− h fe RC R L
hie ( RC + R L )
and
Ai = h fe
RB
RC
hie + R B ( RC + R L )
hie and hfe can be found on the data sheet of the transistor, and they should be read
(approximated) from the working point of the idle current IQC.
T2.20 Draw the small signal model for a common emitter amplifier and approximate the values of the
output and input resistances from it.
T2.21 How can the input and output resistances be measured like this?
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