Small Amplifier

7/29/2019 Small Amplifier

1/19

Small amplifier

1. INTRODUCTION

In the small-signal, the amplifier transistor operates in the active area of the outputcharacteristics (output characteristics). In this area, the operation of the transistoramplifier is almost linear and can be modeled as a two-terminal network withparameters h (for low frequency) or the parameter Y (for high frequencies). Using thismodel, some important quantities such as voltage gain, current gain, input resistanceand output resistance, the small berisyarat bertatarajah transistor amplifier commonemitter (common emitter, CE), common base (common base, CB) and commoncollector (common collector, CC) can be determined.

This experiment was the second of two experiments on the transistor. equivalent circuit

of the transistor. transistors to build hybrid-In the first experiment, the parameters

measured hybrid- equivalent circuit of the transistor built inIn this experiment, a smalltransistor amplifier berisyarat experimental results are reviewed and compared withresults calculated from the equivalent circuit parameters h (for low frequency) andequivalent circuit parameters of Y (for high frequencies) which is derived from hybrid-the first experiment. Given this, the experiment carried out after the first experiments

performed. The same circuit used for both experiments to compare the results ofexperiments and calculations in this experiment can be carried out by means.

In this experiment, the voltage gain, current gain, input resistance and output resistanceof the small-signal transistor amplifier bertatarajah common emitter, common base andcommon collector, and the results obtained are compared with theoretical calculationsbased on the equivalent circuit parameters h (for low frequency) and equivalentcircuitparameter Y (for high ferkuensi).

2. THEORY

In the small-signal, the amplifier transistor operates in the active area of the outputcharacteristics (output characteristics). In this area, the operation of the transistoramplifier is almost linear and can be modeled as a two-terminal network withparameters h (for low frequency) or the parameter Y (for high frequencies). Using thismodel, some important quantities such as voltage gain, current gain, input resistanceand output resistance, the small berisyarat bertatarajah transistor amplifier commonemitter (common emitter, CE), common base (common base, CB) and commoncollector (common collector, CC) can be determined.

Figure 1 below shows a two-terminal network representing a transistor amplifier.


2/19

Figure 1

Here are four variables that (V1, I1) at the input terminals and (V2, I2) at the outputterminal. If I1 and V2 are taken as independent variables, we obtain the model

parameters h, if V1 and V2 are taken as independent variables, we obtain the modelparameters Y.Both these models are discussed below.

The equivalent circuit parameters h (hybrid)The equivalent circuit parameters h (hybrid) can be used in the analysis of small

berisyarat transistor amplifier at low frequencies.

In Figure 1, draw I1 and V2 as the independent variables and using the superpositionprinciple (principle of superposition), we find

V1 = H11 h12 I1 + V2 (Equation 1a)H21 I1 + I2 = V2 H22 (Equation 1b)

According to conventional notation in the amplifier transistor,

Hi Ii Vi = Vo + hr (Equation 2a)I o = ht ho Ii + Vo (Equation 2b)

or in matrix form [h],

(Equation 3)

Voltage gain, current gain, input resistance and output resistance in terms of theparameters h and the burden of obstacles can be published as follows:

Figure 2

Figure 3

The gain of the current:


3/19

AI = =(Equation 4a)

Input resistance:

Ri = = hi + hrAIRL(Equation 4b)

Voltage gain (a):

Gv = ==

(Equation 4c)

Voltage gain (b):

Gvs = =(Equation 4d)

The resistance of the output:

Ro = =(Equation 4e)

Conversion tables of the matrix [h] CE, [h] CC and [h] CB lowered below:

[H] CC CB CEhi Hie Hie

1 hr hre

hf hfe - (1 + hfe)

hce ho Hoe

where he = hiehoe - hrehfe.

The equivalent circuit parameters Y


4/19

Y equivalent circuit parameters can be used in the analysis of small berisyarat transistoramplifier at high frequencies.

In Figure 1, draw V1 and V2 as the independent variables and using the superposition

principle (principle of superposition), we find

I1 = Y11 Y12 V1 + V2 (Equation 5a)I2 = Y21 Y22 V1 + V2 (Equation 5b)

or in matrix form [Y],

(Equation 6)

The parameter Y is a complex function of frequency and can be defined as follows:

Y11 = post-entry circuit (Equation 7a)Y12 = = short circuit reverse transfer graduates (Equation 7b)Y21 = = graduate next transfer circuit (Equation 7c)Y22 = = graduate output short circuit (equation 7d)

Leavers input, output lepasaan, multiple current and voltage gain can be obtained asfollows:

Figure 4

Yi = (Equation 8a)

Yo = (Equation 8b)

AI = Equation 8c)

AV = (Equation 8d)

3. EXPERIMENTAL

Objectives


5/19

Recovery of voltage gain, current gain, input resistance and output resistance of acommon emitter transistor amplifier bertatarajah (common emitter, CE), a commoncollector (common-collector, CC) and the common base (common base, CB) for lowand high frequencies and comparing This results in the theory (using the matrix [h] forlow frequencies and the matrix [Y] for high frequency).

Apparatus

Resistor circuit boardsThe variable resistor power supplyCapacitor signal generatorMeter-meter transistorsMultimeter

3.1 Low Frequency(I) a common-emitter (CE)

The circuit shown in Figure I is connected.

Figure I

and measured., 10 k 1 k With a small signal (Vi = 10 mV peak to peak), VS, andVo in the case of RX = AI, Ri, GV, GVS and Ro calculated. The results are comparedwith theory.


6/19

(Ii) Common Collector (CC)

The circuit shown in Figure II is connected.

Figure II

. and 300 , 500 With V = 0.4 V, V, and Vo measured for the case Rx = AI, Ri, GV,

GVS and Ro calculated. The results are compared with theory.

(Iii) Common sites (CB)

The circuit shown in Figure III is connected.

Figure III

and measured., 10 k 1 k With V = 10 mV, V, and V0 the case of RX = AI, Ri, GV,

and Ro Gvs calculated. The results are compared with theory.

3.2 High Frequency (Optional)

Frequency signal generator set at 500 kHz.

Count carried out by the matrix [Y] at a frequency f = 500 kHz. found in the EUAt first,[Y] CE derived from high-frequency model of the hybrid- measurement of transistor

parameters.5A: Hybrid- Later, [Y] CC and [Y] CB available.

Step (i), (ii) and (iii) above is repeated at a frequency of 500 kHz. Distortion is known notto.

4. RESULTS

4.1 Decision theory

Low-frequency case


7/19

In U.E. equivalent circuit for low frequencies were found with the parameters

priceless. measurement of transistor parameters, hybrid-5A: Hybrid- Of these, thematrix [h] is obtained that

[H] CE =

=

(I) bertatarajah transistor emitter amplifier (common emitter, CE)

RX =

= 4.8 + 100 k RL = 4.7 kAI = = = = - 69.7

Ri = = hi + hrAIRL = 3367

Gv = == = = -99.4

Gvs = = = (-99.4) = -25.0

Ro = = = = 1.13 k

RX = 10 k

k = 3:24 / / 10 k RL = 4.8 k

AI = = = = -76.3


Gv = = = = -73.4

Gvs = = = = -18.5 -73.4

Ro = = = = 1.13 k

RX = 1 k

/ / 1 = 828 k RL = 4.8 kAI = = = = -89.5


Gv = = = = -22.0


8/19

Gvs = = = = -5.54 -22.0

Ro = = = = 1.13 k

(Ii) common collector amplifier transistor bertatarajah (common-collector, CC)

Hie = HRC = 1HIC = 3367

SHFC = - (1 + hfe) = - (1 +95.2) = -96.2 hoc = Hoe = 76.3

Thus, [h] CC =

RX =

= 4.8 + 100 k RL = 4.7 kAI = = = = 70.4

Ri = = hi + hrAIRL = 3367 + (1) (70.4) (4.8k) = 341.2 k

Gv = == = = 0990

0990Gvs = = = = 0888

Ro = = = = 426.1

RX = 500

RL = 4.8K / / 500 = 453AI = = = = 93.0

Ri = = hi + hrAIRL = 3367 + (1) (93.0) (453) = 45.5 kGv = =

= = = 0926

0926Gvs = = = = 0499

Ro = = = = 426.1

RX = 300


9/19

RL = 4.8K / / 300 = 282AI = = = = 94.2

Ri = = hi + hrAIRL = 3367 + (1) (94.2) (282) = 29.9 k

Gv = == = = 0888

0888Gvs = = = = 0385

Ro = = = = 426.1

(Iii) bertatarajah common base transistor amplifier (common-base, CB)

In theory, it is found

) = 0.2566 he = hiehoe - hrehfe = 3367 (76.2

Hib = = = 35HRB = = = 2667 x 10-3

HFB = = = -0.9896

Shob = = = 0793

Thus, [h] CB =

RX =

+ 100 = 2.8 k RL = 2.7 kAI = = = = 0.9874

Ri = = hi + hrAIRL = 35 + (2.667m) (0.9874) (2.8k) = 42.4

Gv = == = = 65.2

Gvs = = = (65.2) = 4:59

Ro = = = = 191.3 k

RX = 10 k


10/19

k = 2:19 / / 10 k RL = 2.8 kAI = = = = 0.9879

Ri = = hi + hrAIRL = 35 + (2.667m) (0.9879) (2.19k) = 40.8

Gv = = = = 53.0

Gvs = = = (53.0) = 3.60

Ro = = = = 191.3 k

RX = 1 k

/ / 1 = 739 k RL = 2.8 kAI = = = = 0.9890

Ri = = hi + hrAIRL = 35 + (2.667m) (0.9890) (739) = 36.9

Gv = = = = 19.8

Gvs = = = (19.8) = 1:22

Ro = = = = 191.3 k

4.2 Experimental Results

i) a common-emitter (CE)

VS / Vo mVpp / VppRX / k

1:20 38.010 38.0 0.961 38.0 0.36

Calculation:

Vi = 10 mVPP

RX =RL = 4.8k

AIi = = = 2.8

AIo = = = 250

AI = = - = -89.3


11/19

Ri = = = 3571

Gv = = = -120

Voltage gain is negative because there are 180o phase difference between the output

vs input VI

Gvs = = = - 31.6

Ro = = = 4800

RX = 10 k

RL = 3.24 k

AIi = = = 2.8

AIo = = = 296

AI = = - = -105.7

Ri = = = 3571

Gv = = = -96Voltage gain is negative because there are 180o phase difference between the outputvs input VI

Gvs = = = - 25.3

Ro = = = 3.24 k

RX = 1 k

RL = 828

AIi = = = 2.8

AIo = = = 435

AI = = - = -155.4

Ri = = = 3571

Gv = = = -36

Voltage gain is negative because there are 180o phase difference between the outputvs input VI

Gvs = = = - 9:47


12/19

Ro = = = 828

(Ii) Common Collector (CC)

VS / Vo Vpp / VppRX /

0400 00:44500 0.54 0.220300 0.56 0.148

Calculation:

Vi = 0.4 VPP

RX =RL = 4.8k

AIi = = = 1:03

AIo = = = 83.3

AI = = = 80.9

Ri = = = 388.3 k

Gv = = = 1.00

Voltage gain is positive because there is no phase difference between the input vsoutput VI

Gvs = = = 0.9091

Ro = = = 4.8 k

RX = 500

RL = 453

AIi = = = 3:59

AIo = = = 485.7

AI = = = 135.3

Ri = = = 111.4 k


13/19

Gv = = = 0550


Gvs = = = 0407

Ro = = = 453

RX = 300

RL = 282

AIi = = = 4.10

AIo = = = 524.8

AI = = = 128

Ri = = = 97.6 k

Gv = = = 0:37


Gvs = = = 0264

Ro = = = 282

(Iii) Common sites (CB)

VS / Vo mVpp / mVppRX / k

40 18010 40 1401 40 48

Calculation:

Vi = 10 mVPP

RX =

RL = 2.8k

AIi = = = 53.6

AIo = = = 64.3

AI = = = 1:20


14/19

Ri = = = 187

Gv = = = 18


Gvs = = = 4.5

Ro = = = 2.8 k

RX = 10 k

RL = 2.19 k

AIi = = = 53.6

AIo = = = 63.9

AI = = = 1:19

Ri = = = 187

Gv = = = 14


Gvs = = = 3.5

Ro = = = 2.19 k

RX = 1 k

RL = 739

AIi = = = 53.6

AIo = = = 65.0

AI = = = 1:21

Ri = = = 187

Gv = = = 4.8


15/19


Gvs = = = 1.2

Ro = = = 739

5. COMPARISON OF RESULTS

5.1 Common Emitter (CE)

Rx = Rx = 10k Rx = 1k QuantityExperiment Theory Experiment Theory Experiment Theory

AI -69.7 -89.3 -76.3 -105.7 -89.5 -155.4

3571 3367 3367 3571 Ri 3367 3571

Gv -99.4 -120 -73.4 -96 -22.0 -36Gvs -25.0 -31.6 -18.5 -25.3 -5.54 -9.47

828 k 13.1 13.1 k 24.3 k Ro 13.1 k 4.8 k

There are similarities and also differences between the results of theoretical andexperimental results. Results for Ro shows a huge difference, while the values for theRI is approximately equal value. For the decision to GV Gvs, results obtained from thetwo parts more or less the same can be said roughly. However, it appears that theresults are the same signs of positive or negative signs on both sides of the samereading. In addition, the order of magnitude of all quantities are agreed.

5.2 Common Collector (CC)

Rx Rx = 500 = 300 Quantity Rx =Experiment Theory Experiment Theory Experiment Theory

AI 70.4 80.9 93.0 135.3 94.2 128

k 97.6 k 29.9 k 45.5 388.3 111.4 k Ri k 341.2 kGv 0,990 1.00 0,926 0.55 0,888 0.37Gvs 0,888 0.9091 0,499 0,407 0,385 0,264

453 282 426.1 426.1 426.1 Ro 4.8 k


16/19

Available theoretical results and experimental results are not so agree, especially inRi.The values for AI, and Ro showed a slight difference but not that big gap. Has beenfound that the GV and Gvs to theory and experiment is similar, especially the Gvs. Itwas found that the results are the same sign and order of magnitude of all quantities areagreed.

5.3 Common sites (CB)

Rx = 10 k = 1 k Rx = Rx QuantityExperiment Theory Experiment Theory Experiment Theory

AI 0.9874 1.20 0.9879 1.19 0.9890 1.21

36.9 187 187 187 Ri 42.4 40.8Gv 65.2 18 53.0 14 19.8 4.8Gvs 4.59 4.5 3.60 3.5 1.22 1.2

739 k 19.3 19.3 k 19.2 k Ro 19.3 k 2.8 k

Available theoretical results and experimental results are not so agree, especially in the

GV, Ro and Ri. The values for AI and Gvs shows enormous similarities, especially theGvs where both experimental and theoretical values is very similar. It was found that theresults are the same sign and order of magnitude of all quantities are agreed.

6. REPORT

Publish all diberkan equations above:

Figure 6

Parts of the input circuit

VI = Vo hi II + hr (Equation 1)

Parts of the output circuit

Io = ht ho Ii + Vo (Equation 2)

Found Vo = Io RL parts to the equation 2, then equation 2 to

Io = ht Ii - Io ho RL (Equation 3)

AI can be found by equation 1 and equation 3, the

= H - ho RL or =AI = -Then

AI = (proven)


17/19

To get impedan input, we need to look into the input circuit, it was found

Rin = = = hi + hr (Equation 4)Replace IoRL =- Vo = AIIIRL in equation 4, we find

Rin = hi + hrAiRL (proven)

The gain of the voltage, GV = Vo / VI (Equation 5)

Found Vo = VI = IiRI AiIiRL and substituting in equation 5

Gv =substitute for the AI = and Rin = hi + hrAiRL into and simplify, we will find

Gv = = (proven)

If Vs is also taken in consideration, the

Gvs =

Impedan output is Ro = Vo / Io

From Io = ht ho Ii + Vo divide both sides by Vo

go = h + ho (Equation 6)

With V = 0, and take the KVL to the circuit input, we find

-II (hi + Rs) - hrVo = 0

= Substituting in equation 6

go = ho-

Ro = 1/go = (proven)

7. DISCUSSION

Show the extent to which a measure AI, Ri, GV, GVS and Ro equal to the count.

Comparison of the values of measurements and calculations are shown above. Thedifference between the experimental and theoretical values depend on the connection,


18/19

whether CE, CC or CB. Overall, the calculations and measurements agree, especially inthe count Gvs. In addition values for GV and AI showed little difference for the threetypes of connections. However, the order of magnitude of all quantities are to agree withone another.

Discuss the characteristics AI, Ri, GV, GVS and Ro for the transistor amplifierbertatarajah CE, CC and CB.

Characteristics of AI, Ri, GV, GVS and Ro is shown in the table below:

The quantity of CB CC CE

1Higher and Higher negative AIRi High Medium Low

a HighHigher and negative GVAnd negative GVS Low Medium MediumRo High Low Medium High

).Negative values of AI, GV and GVS show that the signal input and the output is theopposite phase (phase difference = 180

Comparison of measurements and calculated values of AI, Ri, GV, GVS and Ro are thedifferences in these values. This may be due to the following factors:

to replaca) Resistors are not supplied as specified in the figure, for example, we

use the resistor 50 k and 40 k .e the 47 k and 39 k

b) Our calculations do not take into account the resistance measuring meters.

c) This experiment and the experiment 5a UE does not run on the same day and theexperiment might have been different.

8. CONCLUSION-h equivalent circuit parameters can be used in the analysis of small berisyarattransistor amplifier with small input frequency (ie 1 kHz).

Configure CE, CC and CB are the characteristics of current gain, voltage gain, inputresistance and the resistance of different products as examined in this experiment.


19/19

9. REFERENCES

a) Edwin C. Lowenberg, Electronic Circuits, McGraw-Hill Book Company, 1983.

b) Jacob Millman, Christos C. Halkias, Integrated Electronics: Analog And DigitalCircuits And Systems, McGraw-Hill Book Company, 1971.

Documents

Small Amplifier