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104 Cards in this Set
- Front
- Back
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what is the purpose of audio amplifiers?
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to provide uniform amplification of all signals within the audio frequency range
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what is the audio frequency range?
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20Hz to 20KHz
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______ audio amps will cause distortion at certain frequencies
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some
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what is distortion?
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any undesired change in the waveform
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what is high fidelity?
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reproduction so perfect that it duplicates the original
(faithful in reproduction) |
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high-fidelity audio amps are the only ones designed to accommodate the ______ range
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entire
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signal voltage amplifiers primary consideration is ______ gain
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voltage
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power amps primary consideration is delivery of a large amount of ______ at the output with minimum distortion of the signal
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power
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Single-ended audio amplifier operated at Class ______
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Class A
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Single-ended audio amplifier operated at Class A therefore ______ efficiency
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low
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Class B Push-Pull Audio Amp
power output is more than ______ of a single-trans stage requires ______ the drive of a single-trans stage requires input of ______ signals = in amplitude and opposite in polariy. Class B causes ______ |
twice
twice 2 crossover |
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what is this?
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center-tapped transformer phase-splitter
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center-tapped transformer phase-splitter:
provides ______ output power and gain |
max
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what is this?
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single stage split load phase inverter
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single stage split load phase inverter:
application used for ______ push-pull amp when good frequency response is of greater importance than high gain provides better ______ than is possible with a transformer phase splitter |
driving
frequency response |
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what is this?
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2 stage phase inverter paraphase amp
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2 stage phase inverter paraphase amp:
application-used to produce sufficient power to _____ a high power push-pull stage and provide good ______ provides more than ______ the power output of a single stage phase inverter |
drive
frequency response twice |
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what is this?
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complementary-symmetry (push-pull) audio power amp
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complementary-symmetry (push-pull) audio power amp:
used where ______ and ______ are required requires no ______ operated at Class ______ for ______ efficiency with ______ distortion |
high output and fidelity
requires no phase splitter operated at Class AB for good efficiency with minimum distortion |
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taking bypass capacitor off will cause
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degenerative feedback
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uneven amplification across the audio-frequency band results in ______ at certain frequencies
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distortion
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degenerative feedback is used in audio amp's to______ frequency response
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broaden
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An unbypassed emitter resistor is a simple way to obtain ______
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degenerative feedback
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another way to obtain degen feedback is to return a portion of the ______ (180degrees out of phase) signal to the ______
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output
input |
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coupling between audio amp's stages affect ______
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freq response
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direct coupling provides the ______ frequency response
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best
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RC coupling is simple, inexpensive, and provides excellent freq response within the ______ band
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Audio frequency
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transformer coupling provides ______ freq response with the possibility of additional ______
______ impedance matching. Heavy, bulky and expensive |
good
gain excellent |
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Impedance coupling has a ______ use in audio amp's
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limited
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Impedance coupling ______ with frequency resulting in uneven response. may be useful where a selected portion of the AF band is to amplified
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varies
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Noise is desirable/undesirable ?
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noise is undesirable in all applications where fidelity is important
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Noise factor is effect by
______ , ______ , and ______ |
operating point, signal source resistance, frequency
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operating point - the best condition for low noise is operating at ______ collector voltages and ______ emitter currents
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low, low
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signal source resistance - best operation is obtained with an input resistance of ______ to ______ ohms
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100 to 3000 ohms
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high frequency = ______ noise factor
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lower
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what is an oscillator?
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a circuit that generates alternating current at a frequency determined by the values of its components and of a constant peak amplitude, maintains this waveform within certain limits.
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oscillator is used to provide a ______ frequency for radio or radar transmitters & receivers (timing)
converts ______ to ______ |
constant
DC to AC |
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what are the basic components of a oscillator?
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FDN, an amp, and a feedback arrangement
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FDN is the heart of the oscillator. Establishes the operating frequency of the oscillator, acts as a ______, allowing only the desired frequencies to pass
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filter
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the voltage fed back from the amp must be ______ with voltage in the FDN
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in phase
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describe amp stability
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the ability of an oscillator to maintain a constant-amplitude output waveform.
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the less the deviation from a predetermined amplitude, the better the ______
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amplitude stability
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describe frequency stability
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the ability of an oscillator to maintain the desired operating frequency . The less the frequency deviates from the desired frequency the better the frequency stability
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a constant ______ is the prime requirement for good frequency stability
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DC supply voltage
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what are the two broad categories according to their output waveforms?
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nonsinusoidal and sinusoidal
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what are the two general classes of oscillators?
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series fed
parallel fed |
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describe series fed oscillator
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an osc in which the DC current path is through the resonant tank circuit. (Ground on the bottom of the tank)
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describe parallel fed oscillator
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(shunt fed). An osc in which DC current does not flow through the tank circuit. (no ground on the bottom of the tank)
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what is the identification feature of the Armstrong Osc?
what does it look like? |
Tickler coil
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in Armstrong Osc
FDR is comprise of ______ and ______ |
L1 and C1
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In Armstrong Osc
Q1 is the ______ |
amplifier
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In Armstrong Osc
Feedback Network (tickler coil) is composed of ______ and ______ ______ allows for adjustment of collector current |
L2 and R2
R2 |
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The tickler coil uses transformer action to ______ feedback
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couple
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what is the identification feature of the Series Fed Hartley Oscillator?
what does it look like? |
split or tapped coil
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what is a disadvantage of the series fed Hartley Osc?
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instability
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series fed Hartley Osc FDN consists of:
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a tuned tank, composed of L1, L2, and C2
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series fed Hartley Osc amplifier consists of ______ and associated componenets
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Q1
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series fed Hartley Osc feedback network are:
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split coils, L1 and L2
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Shunt fed Hartley Osc is also identified by
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split coilds
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Shunt fed Hartley Osc;
No DC current flow through the ______. This improves the stability of the circuit. |
tank circuit
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Colpitts Osc is identified by the ______
what does it look like? |
split capacitor
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Colpitts Osc is more ______ than Armstrong or Hartley Osc
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stable
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Colpitts Osc are ______ fed
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shunt
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describe the piezoelectric effect?
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the property of certain crystals to produce a voltage when subjected to mechanical stress (compression, expansion, twisting), or conversely to produce a mechanical stress when subjected to voltage
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the frequency of vibrations is determined primarily by the ______ of the crystal
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thickness
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Resonant frequency mode (series mode) acts like a series resonant circuit.
______ Z, ______ stability, and can generate ______ frequency, ______ expensive, ______ output amplitude, used for filters and osc operating at ______ frequency |
Low Z, max stability, higher frequency, more expensive, lower output amplitude, high frequency
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Anti resonant frequency mode (parallel resonant circuit)
______ Z, extremely ______ Q, ______ stability, More economical to produce than series mode crystals. primarily used below ______ MHz, ______ output amplitutde in the series mode. operates over a ______ range of frequencies |
High Z, extremely high Q, good stability, below 20MHz, higher output, operates over a wide range
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FDN composed of ______ in place of the tuned tank
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Y1k
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draw the FDN & Feedback Network portion of the Crystal controlled colpitts Osc
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.
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Crystal controlled colpitts Osc:
amount of regenerative feedback depends on the relative ______ of R1/R2 and C1/C2 |
sizes
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what is this?
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RC Phase Shift Oscillator
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RC Phase Shift Oscillator:
FDN consists of ______ or more RC Phase Shift networks |
3
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RC Phase Shift Oscillator:
The amount of phase shift is determined by the ratio of ______ to ______ |
resistance to XC
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RC Phase Shift Oscillator:
Any phase shifted more or less than ______ will be degen or canceled |
180 degrees
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describe: avalanche device
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a device that operates in voltage breakdown region, with resistance up to the point of breakdown, then conducts at minimum.
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what is breakdown voltage?
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voltage at which sudden increase in reverse current across PN junction occurs
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what is Zener effect?
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reverse-bias breakdown below 5 volts
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what is avalanche effect?
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breakdown above 5 volts
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breakdown is determined by
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type of semiconductor material
type of doping material level of doping |
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Zener Diode:
symbol and reference designator? |
D, VR
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Zener operates in ______
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breakdown region (reverse bias)
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breakdown voltage is determined by
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type of semiconductor material
type of doping material level of doping |
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Tunnel Diode:
symbol and reference designator? |
(D, CR)
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Tunnel Diode:
biased to operate in ______ |
negative-resistance region
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Varactor Diode:
symbol and reference designator? what does it look like? |
(D, CR)
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Varactor Diode behaves like a ______
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variable resistor
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Varactor Diode:
used in tunnel circuits-allows DC voltage to be used for ______ |
remote or auto tuning
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Varactor Diode:
reverse biasing ______ depletion region As depletion region increases, capacitance ______ |
increases
decreases |
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Varactor Diode:
what is the capacitance formula? |
C = KA / d
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explain C = KA / d
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c = capacitance
A = plate area/junction area K = dielectric constant d = distance between plates/depletion region |
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what is JFET
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junction field effect transistor
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JFET
symbol and reference designator? |
Q
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JFET:
constructed solid bar semiconductor material (N or P) with area of opposite-type material diffused into each ______ |
side
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JFET:
uses electrostatic field to ______ current flow |
control
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JFET:
draw or describe what this looks like then label it |
.
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JFET:
voltage applied to the gate controls _______ from the source to the drain |
current flow
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what is MOSFET?
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metal oxide semiconductor field effect transistor
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MOSFET:
symbol and reference designator? |
Q
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MOSFET:
extra high input ______ (#) ______ frequency response ______ gain factor (#) |
impedance (10 Mohms to 10(tothe12th)Mohms
excellent high (5 to 50) |
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MOSFET enhancement mode:
normally ______, must be biased ______. current flow from source to drain controlled by variations in gate ______ |
ON, ON, voltage
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MOSFET Depletion Mode:
normally ______ , must be biased ______ Gate ______ used to depletion current carriers in channel |
ON, OFF, voltage
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what is this?
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Enhancement MOSFET?
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what is this?
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Depletion MOSFET
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what is this?
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dual gate
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