EXPERIMENT NO. 1
COMMON-EMITTER AMPLIFIER IMPEDANCE, POWER AND PHASE
RELATIONSHIOPS
I. OBJECTIVES:
1. To Measure the input and output impedance of a Common-Emitter Amplifier.
2. To observer with an oscilloscope, the phase of the input and output signal voltage on
a Common Emitter Amplifier.
3. To determine the decibel power gain.
II. DISCUSSION:
The input signal Vi is applied to the base of the transistor while output Vo is off the
collector. In addition, recognized that the input current Ii is not the base current but the source
current, while the output current Io is the collector current. The small signal ac analysis begins by
removing the dc effects of Vcc and replacing the dc blocking capacitor C1 , C2 and C3 short
equivalents resulting in the network of Fig 4-1 (a).
Note in the Fig. 4-1(a), that the common ground of the dc supply and the transistor emitter
terminal permits the relocation of RB and RC parallel with the input and output sections in
addition, note the replacement of the important parameters, Zi, Zo, Ii and Io.
III. MATERIALS AND EQUIPMENT:
Variable related dc source
Oscilloscope; DMM; and sine wave generator
½ w 460Ω, 550Ω, 2- 11Ω, 4.7Ω, 8.2Ω, 20Kω
2- 25 μF/50V, 100 μF/50 V
2N3904, In4001, or equivalent semiconductors
SPST switch; 2 – w 5k Ω potentiometer
IV. PROCEDURE:
1. Connect the circuit of Fig. 3-1a. Switch the power on and adjust the AF sine wave
generation for 1000Hz and the generator level, Vout for 75% maximum undistorted output
as observer with an oscilloscope, (Connected across the output)
a. Note: Rx is 1000 Ω resistor and not a potentiometer
2. Using an oscilloscope, measure and record in table 3.1 the peak to peak voltages of (a)
VAC1 (b) VBC or Vin and (c) Vout
3.
Computer Vx across Rx by subtracting Vac from VAC, Record in the table 3.1 and also
compute and recond im and Rin
Table 3.1 Common- Emitter Impedance and Power Measurements
V p -p
Steps VAC
Vac/ Vin Vout
VAC + Vac
Vx/
im mA Rin Ω
Ω
Rout
Gain
Voltage
AB
Power,
OUTPUT IMPEDANCE
4. Maintain the input-signal level, Connect a 500 Ω rheostat as Fig. 3.1b across the output.
Adjust Rout until Vout equals one half (1/2) the output measured in step 2(c).
5. Measure and record resistance Rout (Remove Rout from the circuit). This is then output
impedance of the amplifier. For the power gain, compute and record H in Table 3-1 and
also the voltage gain of the current under load.
PHASE RELATIONSHIP
6. Power off. Remove Rx from the circuit and connect points A to B. Connect the half-wave
rectifier circuit shown in Fig. 3-3. The 1000 Hz signal from the generator is complex to the
input of half-wave rectifier. Output of half-wave rectifier is connected as the AF signal
source for the Common-Emitter in Fig. 3-1.
7. Power on. Reset the signal generator so that Vin is at the same peak voltage level as in step
2b.
8. With an oscilloscope, observe the two cycles of the input waveform. Draw this waveform.
9. Also Observe the two cycles of the output waveform. Draw them in proper time phase with
the input in step 8.
V. CONCLUSION:
VI. QUESTION:
1. In measuring Vx directly, why would it be necessary to use a “floating” oscilloscope?
Why is the use of “floating” instrument generally not recommended?
2. What is the effect an input impedance of removing by pass capacitor C3 in Fig. 3-1?
Refer to your data to substantiate your answer.
3. What is the phase relationship between the input and output signal of Common-Emitter
amplifier? Ws this relationship confirmed by the results of your experiment? Explain
how.
4. Is the input impedance of a Common-Emitter fixed quantity? Explain your answer
EXPERIMENT NO. 2
AC COMMON BASE AMPLIFIER
I.
OBJECTIVES
1. To investigate the operation of common base amplifier.
2. To measure the loaded voltage gain.
II.
DISCUSSION
The common-base configuration is characterized as having a relatively low input and high
output impedance and a current gain less than 1. The voltage gain, however, can be quite large.
The transistor output impedance ro is not included for the common-base configuration because it
is typically in the megohm range and can be ignored in parallel with the resistor Rc.
The fact that the load is connected between the collector and base terminal isolates it from
the input circuit, and Zi remains essentially the same for no-load or loaded conditions. The
isolation that exits between input and output circuits also maintains Zo at a fixed level even
though the level of Rs may change.
III.
MATERIALS AND EQUIPMENTS:
2-0-15V 𝑉𝐷𝐶 Power Supply (𝑉𝐶𝐶 )
1-10kΩ 1⁄4 watt resistor (𝑅𝐸 )
1-Digital Tester
1-1kΩ 1⁄4 watt resistor (𝑅𝑐 )
1- Oscilloscope (Dual Trace)
1-10kΩ 1⁄4 watt resistor (𝑅𝑙 )
1- Signal Generator (100Hz-1MHz
1-2N3904 transistor or equivalent
1-100µF capacitor at 25V DC (𝑐𝐸 )
1-460kΩ 1⁄4 watt resistor (𝑅𝑙 )
1-2.2µF capacitor (𝑐𝑐 )
WIRING DIAGRAM:
IV.
PROCEDURES
1. Wire the circuit as show above, omitting the signal generator and power supply.
2. Apply the 9-volt supply voltage to the breadboard. With DMM, measure the
transistor dc emitter and collector voltage with respect to the ground. Record the
result in Table 4.1.
3. Determine the expected valued of two voltage assuming a dc base-emitter voltage
drop of 0.7V and compare them with the measured values in the Table 4.1.0
4. Connect channel 1of the oscilloscope at point A (Vin) and channel 2 to point B
(Vout). Then connect the signal generator to the circuit as shown in Fig. 3. Adjust
the sine wave output level of the generator of 25m Vp-p at a frequency of 5kHz.
If you cannot reach 25mV, adjust Vin. Observe that the output signal level (Vout)
is greater than the input level. Vout is in phase with respect to the input.
5. Using the measured value for the dc-emitter voltage obtained in step-2, calculate
the dc quiescent emitter current and the resultant transistor ac emitter resistance,
re. Record these values in Table 4.2.
6. Calculate the voltage gain from emitter to collector and record the result in Table
4.3. Now, measure the actual voltage gain by dividing the peak-to-peak output
voltage (Vout) by the peak-to-peak voltage (Vin). Record the result in Table 4.3.
7. Removed RL. Observe that the output voltage level increases. It does because the
load resistance affects the voltage gain of the amplifier stage. As in step 5,
experimentally, determine the voltage gain by measuring Vout and Vin. Record
the result in Table 4.3.
V.
DATA AND RESULT
TABLE 4.1
Parameters
𝑽𝑬
𝑽𝑪
𝑰𝑬
Expected Values
Measured
Values
% Error
TABLE 4.2
Parameters
𝑰𝑬 Calculated
𝑰𝑪 Calculated
TABLE 4.3
Value
𝑰𝑪
Load Resistance
10kΩ
None
Vin
Vout
Measured Gain
Expected Gain
% Error
VI.
VII.
CONCLUSIONS:
QUESTIONS:
1. What are the AC characteristics of a common base amplifier?
2. Determine the gain of the given circuit.
470Ω
EXPERIMENT NO. 3
EMITTER FOLLOWER AMPLIFIER
I.
OBJECTIVE
1. To determine the phase relationship between input and output signal voltage
2. To learn the method used to determine the phase relations in the experiment
circuit.
3. To determine the power gain of the emitter-follower amplifier.
4. To determine the difference between common collector amplifier to common
emitter amplifier.
5. To measure the input and output impedance of the amplifier.
II.
DISCUSSION:
Emitter Follower is a transistor circuit whose voltage gain is approximately unity, exhibits
current and power gain and has high output impedance and low output impedance. The
impedance characteristic of this amplifier makes it useful for impedance matching applications.
The resulting effect is much the same as that obtained with a transformer, where a load is
matched to the source impedance for maximum power transfer through the system. The circuit
also provides isolation between a load in the emitter circuit and a source in the base circuit.
Common example of an emitter-follower is shown in the Fig.5.1 the input ac signal Vin
is coupled by capacitor C1 to the base. The load resistor R2 is connected in the emitter and the
output signal Vout is developed across this unbypassed emitter resistor. The collector is
connected to VCC and it is at ac common or ground, because capacitor acts as a low-impedance
bypass for its collector. C2 can be actual capacitor connected from collector to ground or the
output filter capacitor in the VCC supply. Since the output signal appears between base and
collector and the output signal appears between emitter and ground, it is evident that the collector
is common both to the input and output circuits.
PHASE RELATIONS
Notice that on the positive alteration of the input signal Vm, base current increases fort
his NPN transistor to establish the phase of the input and output signals as a result both collector
and emitter currents increases. The instantaneous emitter voltage Vout, which is equal to out R2,
becomes more positive relative to ground that to the ac signal output. As the base voltage goes
positive, the emitter voltage follows. Similarly, as the base voltage goes negative on negative
alternator of Vin, the emitter voltage less positive and more negative. Therefore the input and
output signals are in phase in an emitter-follower circuit.
Since the phase of the signals (are in phase in an emitter-follower circuit) voltage in the
emitter is the same as that at the base, and since the input signal voltage to the circuit is the
difference between signal voltage on the base and that in the emitter, the effect of the unbypassed
emitter resistor is to provide regenerating or negative feedback to the circuit. The amplifier
therefore “sees” a lower effective input signal (between base and emitter) than Vin.
IMPEDANCE AND GAIN
The following approximate equation is shown below, for the basis of the design.
Av = voltage gain =1
Ai = current gain =1/(1-d)
Ap = power gain =1/(1-d)
Input resistance Rin =RL / (1-d)
Output resistance = Pout = re+ (1-d)(Rb+b)
FROM THE EQUATION
Re and Rb are emitter and the base resistance respectively and RG is the internal
resistance of the signal source. The approximate formulas are valid only for the circuits from
which are formulas were derived and are based on certain assumptions. The voltage gain and
input and output impedance of the emitter-follower amplifier may be determined values of Pin,
Rout, Vin, and Vout, therefore,
Pin = 𝑉𝑖𝑛2 /𝑅𝑖𝑛 = 𝐼𝑖𝑛2 /𝑅𝑖𝑛
III.
MATERIALS AND EQUIPMENTS
Variable regulated low voltage dc source
Oscilloscope; EVM; AF sine – wave generator
½ w 4.7kΩ, 15kΩ, 460Ω
Capacitor; 25µF/50, 100-µF/50
2N2102 semiconductor
Three SPST switches. 5kΩ potentiometer
IV.
PROCEDURE
VOLTAGE GAIN
1. Connect the circuits of Fig.5.1 with power-off. At the generation is set at zero output and
switch S1 closed while be allowing S2 to be open. Connect the oscilloscope across Vout
and adjust it for proper viewing.
Measure the peak-to-peak voltage.
FIGURE 5-1 Experimental Emitter-Follower Amplifier
2. Turn on power and slowly bring of gain of AF generator until 150mV output appears
across point BE. Measure Vout and record in Table 5.1.
Table 5.1 Voltage gain, Input Impedance and Input Power
Vout, V
Vin, V
Gain = Vout/Vin
Vab, V
Im, A
Rin, Ω
𝐼𝑖𝑛2 Rin, W
3. Measure and record input signal voltage and also for the voltage gain.
Open switch S1 and increase AF generator output until Vin at the same as for Vin (point
AC) measure VAB record by table 5.1. Compute also for the input base signal (Iin) using
appropriate formula.
4. Compute the input resistance, Rin substituting Iin and Vin in the formula
Rin= Vin/Iin
Also the input power 𝐼𝑖𝑛2 Rin and record it in table.
5. Again, close switch S1 and reduces generator output until Vout reads 100mV (S2 still
open). Record your measurement for Vout.
6. Close S2. Adjust RL until Vout with load is ½ Vout measured in step 5 and record
Vout/2. Now open again S2 to measure resistance RL. Compute also for the power record
all necessary data in table 5.2.
Vout, V
Vout/2 , V
RL =Rout, Ω
𝑉𝑜𝑢𝑡 2 /Rout, W
Power Gain
Table 5.2
PHASE RELATIONS
7. Drain waveform of the input and output phase on proper time phase.
V.
VI.
CONCLUSION:
QUESTIONS:
1. What is the difference between a common-collector to an emitter-follower
amplifier?
2. Emitter-Follower is primarily used to match a high impedance source to allow
impedance load, why is that so?
3. Referring to your experimental data, what can you say about the voltage gain of
the emitter-follower?
4. Is the size of bias resistor R1? In Fig.5.1 affect input impedance of the circuit?
Justify your answer.
5. Comment about the relationship between the phase of the input and output
waveforms in the emitter-follower.
6. Assume that Vout/Vin =1. Write the approximate formula for power gain and
explain in detail how you can determine the input impedance of the experimental
amplifier.
EXPERIMENT NO.4
COMMON SOURCE JFET AMPLIFIER
USING AC SOURCE
I.
OBJECTIVE:
To investigate the operation of a common-source JFET transistor amplifier using
AC source.
II.
DISCUSSION:
The common source amplifier is one of the three basic FET transistor amplifier
configurations. In comparison to the BJT common-emitter amplifier, the FET amplifier
has much higher input impedance, but a lower voltage gain. In this experiment, the
student will build and investigate a simple /-channel, common source JFET amplifier.
III.
MATERIALS AND EQUIPMENTS:
1-100mV AC power supply
1-12V DC source
1-Oscilloscope
1-Digital tester
1-JFET 2N5566
1-2.2kΩ, 1kΩ, 10kΩ, 100kΩ resistors
1-0.01µF, 1µF, 10µF capacitors
IV.
PROCEDURES:
1. Build the circuit shown in Fig. 6 without the load R=10KΩ.
2. Measure and record the DC voltages at the FET terminals.
3. Then, connect the oscilloscope to various test points (A, B, C and Vo). Draw
and measure the waveforms.
4. Now, try removing Cs then observe and measure the output voltage.
5. Try connecting the load R=10KΩ and repeat procedures 2-4. Then record the
results
V.
DATA AND RESULTS:
Without load:
With Load:
Av expected=
Av expected=
Av measured= Vo/Vi=
Av measured= Vo/Vi=
Vo=
Vo=
Vi=
Vi=
GRAPH:
VI.
CONCLUSION:
VII.
QUESTIONS:
1. What is the purpose of the source bypass capacitor?
2. How do the waveforms seen at the FET’s drain (point C) and the output (Vo)
compare?
3. What kind of waveform, if any , is seen at point B?
4. After removing Cs, did the output decrease as expected?
EXPERIMENT NO. 5
JFET SOURCE FOLLOWER/COMMON DRAIN AMPLIFIER
I.
Objective:
To determine the voltage gain with and without load.
II.
Discussion:
COMMON-DRAIN AMPLIFIER
The common drain FET amplifier is similar to the common collector configuration of the
bipolar transistor. This configuration, which is sometimes known as a source follower, is
characterized by a voltage gain of less than unity, and features a large current gain as a result
of having large input impedance and a small output impedance.
The source follower (common-drain) is used as an input stage to instruments because of its
very high input impedance and low output impedance. The dc bias circuit as identical to that
of the common-source amplifier. For our example, we will assume the same circuit values as
before.
COMMON-GATE AMPLIFIER
Common gate amplifier is the JFET counterpart to the common-base amplifier.
The common gate amplifier has low input impedance, high output impedance (compared to
Zin), and voltage gain that is greater than 1.
A common-gate amplifier is one of the possible configurations of FET electronic
amplifier. It is normally used to convert low impedance to high impedance, but is very rarely
found in practice.
III.
Materials:
Function generator
Variable power supply
Ro=10kΩ
Rs=15kΩ
RL=10kΩ
C1= 10µF
C2= 10µF
Rs= 10kΩ
RL=15kΩ
Transistor 2N5566
IV.
A.
Procedure:
COMMON-DRAIN AMPLIFIER
JFET SOURCE FOLLOWER / COMMON DRAW AMPLIFIER
1. Construct the circuit as shoiwn Fig.7, Using the digital tester, measure the output voltage
and calculate voltage and calculate the voltage without the load.
2. Repeat procedure 1, now with connected load of R=1KΩ
B. COMMON-GATE AMPLIFIER
1. Construct circuit as Fig 8. Without the load, measure the output voltage.
2. Repeat procedure 1 but now connect the R = 1KΩ load.
COMMON GATE
V.
ANALYSIS OF RESULTS:
A. COMMON-DRAIN AMPLIFIER
Without Load:
Measured:
Vo=
Av= Vo/Vi=
With Load:
Measured:
Vo=
Av= Vo/vi=
Computed:
Vo=
Av=
Computed:
Vo=
Av=
B. COMMON-GATE AMPLIFIER
Without Load:
Measured:
Vo=
Av= Vo/Vi=
Computed:
Vo=
Av=
VI.
Conclusion:
VII.
Questions:
With Load:
Measured:
Vo=
Av= Vo/vi=
Computed:
Vo=
Av=
1. There is _______________ between input and output for the ___________ and
____________. Most others have an 180̊ phase shift.
2. The _________ for most FET configurations is determined primarily by For the source
follower configuration is determined by _______ and ____________.
3. The input impedance for the common gate configuration is _______.
4. The magnitude of the gain of FET networks is typically between _____________ and
__________.
5. The _______ and the ________ are low-gain configuration.
EXPERIMENT NO. 6
CASCADED TRANSISTOR AMPLIFIER
I. OBJECTIVES:
1. To measure the operation of an RC coupled, two-stage audio amplifier.
2. To have an understanding about the different methods of coupling.
3. To determine the purpose of cascading amplifiers.
4. To observe the operation of a Darlington Circuit.
5. To measure the dc voltages across the Darlington circuit and the output ac voltage.
II. DISCUSSION:
A popular connection of amplifier stages is the cascade connection. Basically, a cascade
connection in series connection with the output of one stage then applied as input to the second
stage. The cascade connection provides a multiplication of the gain of each stage for the larger
overall gain. Amplifiers, either transistor or vacuum tube may be separated in cascade to extend
the gains possible with single-stage.
There are nine possible transistor cascade arrangements. The most common is the
grounded-emitter-to-grounded-emitter configuration. They are used in sound-reproducing
systems as audio amplifiers, in TV receivers as video (picture) amplifiers, and in many other
applications.
COUPLING METHODS
Transformer Coupling
Remember that the transformer producers induced secondary voltage just for variations in
primary current. With pulsating direct current in the primary, the secondary has an output voltage
only for the ac variations. The steady dc component in the primary has no effect in the
secondary. Transformers make it possible to match the output impedance of the first stage to the
input impedance of the next. Proper impedance matching ensures transfer of power from one
stage to the next.
In Fig. 8, the pulsating dc voltage I the primary produces pulsating primary current. The
dc axis corresponds to a steady value of primary current that has a constant magnetic field, but
only when the field changes can secondary voltage be induced. Therefore, only the fluctuations
in the primary can produce output. Since the Is no output for the steady primary current, this dc
level corresponds to the zero level for the ac output in the secondary.
When the primary current increases above the steady level, this increase produces one
polarity. For the secondary voltage as the field expands, when the primary current decreases
below the steady below, the secondary voltage has reverse polarity as the field contracts. The
result in the secondary is an ac variation having opposite polarities with respect to the zero level.
The phase of the ac secondary voltage may be shown or 180° opposite, depending on the
connections and direction of the windings. Also, the ac secondary output may be more or less
than the ac component in the primary, depending on the turn’s ratio. This ability to isolate the
steady dc component in the primary while providing ac output in the secondary applies to all
transformers with a separate secondary winding, whether iron-core or air-core.
RC COUPLING
This method is probably the most common type of coupling in amplifier circuits. The
coupling means connecting the output of one circuit to the input of the next. The requirements
are to include all frequencies in the desired signal while rejecting undesired components,
Usually, the dc component must be blocked from the input to ac amplifiers. The purpose is to
maintain a specific dc level for the amplifier operation.
In Fig 8.1, the pulsating dc voltage across input terminals 1 and 2 is applied to the
average charging voltage The steady dc component is blocked, therefore, since it cannot produce
voltage across R. However, the ac component is developed across R, between output terminal 3
and 4. The reason is that the ac voltage allows C to produce charge and discharge current through
R.
DIRECT COUPLING
Direct Coupling is also used in cascaded transistor amplifiers. An advantage of direct
coupling is the savings possible in components and the improvement in the frequency response.
Direct coupling is possible using PNP and NPN transistors, PNP and NPN transistors
exhibit a properly known as “complementary symmetry”, that is the polarity of the signal
necessary to increase current in one type is the opposite of that necessary to increase current in
the other.
LINEAR OPERATION
Two or any number or amplifiers operated in cascade may be considered as a single
amplifier w/a single input and single output. When two or more amplifiers are operated in
cascade, the characteristics of the total unit must confirm to the requirements of the application.
For example, if two or more transistor amplifiers in cascade constitute an audio amplifier, the
amplifier must be operated its linear characteristic for distortion less reproduction of sound.
An oscilloscope may be used to test linear operation. An audio sine-wave generator is
used as the signal source. The output of the amplifier is monitored with an oscilloscope. To
determine the range of linear operation, the input signal level is increased from zero to just below
the point of distortion (clipping) in the output. The maximum generator signal which does not
introduce distortion is thud determine and may be measured.
DARLINGTON PAIR
A very popular connection of two bipolar junction transistors for operation as one
“superbeta” transistor is the Darlington connection. The main feature of the Darlington
connection is that the composite transistor acts as a single unit with a current gain that is the
product of the current gains of the individual transistors. If the connection is made using two
separate transistors having current gains of β1 and β2 the Darlington connection provides a
current gain of
If the two transistors are matched so that β1 – β2 the Darlington connection provides a
current gain of
βD – β2
III. MATERIALS AND EQUIPMENT
Variable regulated low-voltage DC source
Oscilloscope; Digital tester; AF generator
½ w 100 Ω, 460 Ω, 550 Ω, 1k Ω, 8.2 Ω, 10k Ω, 20k Ω, 47k Ω
C1 and C3 – 25 μF ; C2 and C4 – 100 μF
2w – 5k Ω potentiometer; SPST switch
2 – 2N3904 transistors
1- 0.5 μF capacitor
1- 330 Ω, 100k Ω, 47k Ω resistor
IV. PROCEDURE
A. FOR CASCADED TRANSISTOR AMPLIFIERS
a. Connect the current of Fig 8-2, a signal generator is set at 100 Hz, Power on.
Close the
Apply
experiment.
switch. Set the output of the power supply at 9V as measured with the DMM.
power to the circuit, monitor and maintain its output at 9V throughout the
b. Connect an oscilloscope calibrated for voltage measurement across the volume
control. Set the generator output at 50Mv. Now connect the oscilloscope at the
collector of Q2, test point 5 (TP5). Slowly increase volume control just below the
point where the sinewave starts.
c. Measure using oscilloscope the voltage peak-to-peak at every test point shown
in Fig. 8.2. Note; You probably not be able to read, directly, the signal level at
TP1. You will determine the level at TP1 indirectly in step 6. Measure and record
in Table 8-2, the dc voltage at every test point and the total current It as read on
M1.
d. Open switch. Again measure and record the peak-to-peak signal level and dc
voltage at every test point.
MEASURING SIGNAL VOLTAGE AT TP1
e. Remove the signal generator from the circuit. Maintain the setting of the volume
control the switch off power. Disconnect the center arm of the volume control. Measure
the resistance from the center arm to ground. Record it in table 8.1. Also measure the
total resistance of the control. Then compute and record the input signal delivered at
TP1 by substituting the measure value RCB and RAB in the formula,
Vin = RCB/RAB x 50 Mv
f. Reconnect the volume control and set of for zero output. Power on. Measure the
total
IT, without signal. Record it in table 8-1.
B. FOR DARLINGTON PAIR
1. Set up the circuit of a Darlington pair in Fig
2. Connect a digital tester to the base-to-emitter of the Darlington transistor.
Measure
and record the result.
3. Connect again a digital tester to the emitter across the 390 Ω resistor. Measure
the
Voltage and record the result.
4. Now, measure the ac output voltage and record the result.
VB (TX) =
VE (TX) =
Vout (AC) =
V. CONCLUSION:
VI. QUESTIONS:
1. What is the purpose of cascading amplifiers?
2. Is the single-stage amplifier as effective as the two-stage amplifier? Justify your
answer by referring to the data
3. Does the experimental procedure suggest a method for isolating the trouble to Q1 or
Q2 in read amplifier such as that in Fig. 8-2. Explain the procedure.
4. What is the range of linear operation of the total amplifier? Refer to the data.
5. What is the voltage of linear operation of the total amplifier? How is the total voltage
gain related to the individual voltage gains of Q1 and Q2?
6. Is there any apparent change in dc voltage level points 4,5, or 6 with s1 open or
closed?
7. A Darlington connection provides ___________ connected as one “super” transistor.
8. A Darlington transistor connection provides a transistor having a ____________,
typically a few thousand.
9. The circuit of Darlington consists of two emitter-followers connected in __________