Summary: Abstract: The Tutorial Problems on Lecture 1 of Analog Electronics.
TUTORIAL NO.1
| Vacuum Tube Era(1895- 1954) | Solid State Era(1954 onward) |
| Incandescent Lamp | White Light Emitting Diodes(still in experimental stage) |
| Cathode Ray Oscilloscope(Raster Scan System)- here we address pixel by pixel | Liquid Crystal Display ( Line at a time display)- here we address row of pixels at a time. |
| Vacuum Diode | PN junction silicon diode(Rectifier-full wave and half wave) |
| Vacuum Pentode | Bipolar Junction Transistor (BJT)or Field Effect Transistor(FET) |
| Thyratron for industrial applications( thyratron was made of gas filled tubes) | Thyristors for industrial applications(Silicon Controlled Rectifiers_SCR made of four layer PNPN diode- these are also rectifiers but here the angle of firing or phase angle for which the SCR is on can be controlled hence it is called controlled rectifier) |
Gas filled discharge tubes produce different colours such as
|
Different Coloured Light Emitting Diodes(LED) or LASER Diodes |
| Photo Multipliers | Photo-diodes(sensors as well as Photo Voltaic Cell or Solar Cell) |
| Photography Cameras | Charge Coupled Devices Camera |
We have studied different applications of Op.Amp. in Basic Electronics Class as well as we have studied Negative feedback Amplifiers. All the op amp amplifiers are negative feed back amplifiers. Each amplifier application approximates one of the ideal controlled sources. In the following example you have got to identify the controlled sources which the particular example of op.amp. application approximates.
(2). Explain how a Non-inverting amplifier is a Transconductance amplifier.
Ans:
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From this equation we get:
(vO -vS )/R2 = i ;
Thus it is an input voltage is being converted to a current i . Hence it is voltage-to-current converter therefore it is an ideal trans-conductance amplifier or voltage controlled current source.
If we are working in terms of output voltage and input voltage then we have VCVS. It is an ideal Voltage Amplifier.
(3) Explain how an inverting amplifier is an ideal trans-resistance amplifier.
Ans:-
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By Norton Theorem At the input terminal:-
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Here all input current i1 flows into R2 because we know that input impedance of the Op.Amp. is very large in tens of Megohms and input voltage at the double ended input of OP.Amp. is practically zero.
Therefore vo = - i2 R2 ;
Here input current is being converted into output voltage;
This is known as current to voltage converter. This is used to convert photo-ionic currents generated in photocells or in photo=diodes into voltage sources with very low source impedance. Here a current source with high internal impedance is converted to a voltage source vo with low internal impedance.
4) Give the characteristics of the four ideal amplifiers and give an example of each.
Ans)
| Ideal Amplifier | Gain | Rin | Rout | Example |
| Voltage Controlled Voltage Source (Voltage Amplifier) |
|
∞ | 0 | Triode,Op-Amp,Emitter follower,voltage follower,source follower, Non-Inv Amplifier |
| Voltage Controlled Current Source (Transconductance Amplifier) |
|
∞ | ∞ | Pentode,Field Effect Transistor(FET) |
| Current Controlled Voltage Source (Transresistance Amplifier) |
|
0 | 0 | Inverting Amplifier |
| Current Controlled Current Source (Current Amplifier) |
|
0 | ∞ | Bipolar Junction Transistor(BJT)(CE & CB)CE->ib controls βfoibCB->ie controls αfoie |
Electronics In Action
MP3 Player Amplifier Characteristics (Used In APPLE IPods)
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Constant voltage Source
Band Width = 20 Hz – 20 kHz
Pout =30 mW in each channel of a stereo head phone
Total Harmonic Distortion = 0.1 % at full power;
This is called a high fidelity system.