Module 8 - Introduction to Amplifiers
Pages i - ix,
1-1 to 1-10,
1-11 to 1-20,
1-21 to 1-30,
1-31 to 1-40,
2-1 to 2-10,
2-11 to 2-20,
2-21 to 2-30,
2-31 to 2-35,
3-1 to 3-10,
3-11 to 3-20,
3-21 to 3-30,
3-31 to 3-40,
3-41 to 3-50,
3-51 to 3-60,
3-61 to 3-70,
AI-1 to AI-3,
Index
COMBINATION PEAKING
is accomplished by using both series and shunt peaking.
LOW-FREQUENCY COMPENSATION is accomplished in a video amplifier by the use of a
parallel RC circuit in series with the load resistor.
2-31
A RADIO-FREQUENCY (RF) AMPLIFIER uses FREQUENCY-DETERMINING NETWORKS
to provide
the required response at a given frequency.
The FREQUENCY-DETERMINING NETWORK in an RF amplifier provides maximum impedance at the
desired frequency. It is a parallel LC circuit which is called a TUNED CIRCUIT
TRANSFORMER COUPLING is the most common form of coupling in RF amplifiers. This
coupling is accomplished by the use of RF transformers as part of the frequency-determining network for the
amplifier.
2-32
ADEQUATE BANDPASS is accomplished by optimum coupling in the RF transformer or by the
use of a SWAMPING RESISTOR.
NEUTRALIZATION in an RF amplifier provides feedback (usually
positive) to overcome the effects caused by the base-to-collector interelectrode capacitance.
ANSWERS TO QUESTIONS Q1. THROUGH Q42.
A-1. The difference between the upper and lower frequency limits of an amplifier.
A-2. The half-power points of a frequency-response curve. The upper and lower limits of the band f
frequencies for which the amplifier is most effective.
A-3. (A) f2 = 80 kHz, f1 = 30 kHz, BW = 50
kHz (B) f2 = 4 kHz, f1 = 2 kHz, BW = 2 kHz
A-4. The capacitance and inductance of the circuit and
the interelectrode capacitance of the transistor.
A-5. Negative (degenerative) feedback.
A-6. It decreases.
A-7. It increases.
A-8. The capacitance of the circuit.
A-9. Peaking coils.
A-10. The relationship of the components to the output-signal path.
A-11. Combination peaking.
A-12. The coupling capacitor (C3).
2-33
A-13. A shunt peaking coil for Q2.
A-14. A decoupling capacitor for the effects of R2.
A-15. A part of the low-frequency compensation network for Q1.
A-16. A series peaking coil for Q1.
A-17. A swamping resistor for L2.
A-18. L1, L2, and R5.
A-19. R9 and C5.
A-20. The gain increases.
A-21. The gain decreases.
A-22. To provide maximum impedance at the desired frequency.
A-23. Yes.
A-24. By changing the value.
A-25. Transformer coupling.
A-26. It
uses fewer components than capacitive coupling and can provide an increase in gain.
A-27. A step-down
transformer.
A-28. A too-narrow bandpass.
A-29. By using an optimally-coupled transformer.
A-30. Low gain at the center frequency.
A-31. A swamping resistor in parallel with the tuned circuit.
A-32. RF transformers are used and
the transistor is neutralized.
A-33. Degenerative or negative.
A-34. By neutralization such as the use of a capacitor to provide regenerative (positive) feedback.
A-35. C2 and the secondary of T1.
A-36. R1 provides the proper bias to the base of Q1 from VBB.
A-37. R2 provides the proper bias to the emitter of Q1.
A-38. The output would decrease. (C4
decouples R2 preventing degenerative feedback from R2.)
A-39. C5 and the primary of T2.
A-40. Four.
2-34
A-41. The dotted lines indicate that these capacitors are "ganged" and are tuned together with a
single control.
A-42. C3 provides neutralization for Q1. 2-35
NEETS Table of Contents
- Introduction to Matter, Energy,
and Direct Current
- Introduction to Alternating Current and Transformers
- Introduction to Circuit Protection,
Control, and Measurement
- Introduction to Electrical Conductors, Wiring
Techniques, and Schematic Reading
- Introduction to Generators and Motors
- Introduction to Electronic Emission, Tubes,
and Power Supplies
- Introduction to Solid-State Devices and
Power Supplies
- Introduction to Amplifiers
- Introduction to Wave-Generation and Wave-Shaping
Circuits
- Introduction to Wave Propagation, Transmission
Lines, and Antennas
- Microwave Principles
- Modulation Principles
- Introduction to Number Systems and Logic Circuits
- Introduction to Microelectronics
- Principles of Synchros, Servos, and Gyros
- Introduction to Test Equipment
- Radio-Frequency Communications Principles
- Radar Principles
- The Technician's Handbook, Master Glossary
- Test Methods and Practices
- Introduction to Digital Computers
- Magnetic Recording
- Introduction to Fiber Optics
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