electronic devices

bode plot

illustrates the frequency response of an amplifier.

bandwidth

The mid-range of an amplifier is called the

Cutoff frequency

any frequency at which the gain has dropped by 3 dB from its mid-range value 

Roll-off

is the rate of decrease in gain below or above the critical frequencies of a filter.

filters

A filter is a circuit that is designed to pass signals with desired frequencies and reject or attenuate others

low pass filter

designed to pass only frequencies from dc up to the cutoff frequency fc.

highpass filter

designed to pass all frequencies above its cutoff frequency fc.

bandpass

designed to pass all frequencies within a band of frequencies

bandstop

designed to stop or eliminate all frequencies within a band of frequencies

logarithmic amplifier

is an electronic circuit that produces an output that is proportional to the logarithm of the applied input

anti-logarithmic

an electronic circuit that produces an output that is proportional to the anti-logarithm of the applied input.

positive feedback or regenerative feedback

Feedback signal is in-phase (0°) with input signal

greater gain

advantages of positive feedback

increase noise

increase instability

reduces bandwidth

disadvantages of positive feedback:

negative feedback

Feedback signal is out-of-phase (180°) with input signal

increase stability

reduces noise

increase bandwidth

advantages of negative feedback

lesser gain

disadvantage of negative feedback

oscillator

Circuit that generates repetitive waveform at a certain frequency which maybe sinusoidal or non-sinusoidal with only a DC supply at the input.

RC oscillator

A type of oscillator that has a combination of resistor and capacitor as feedback elements

LC Oscillator

A type of oscillator that uses a combination of inductor and capacitor as feedback elements

crystal oscillator

The most stable and accurate type of oscillator that uses crystals with piezoelectric effect in the feedback loop to control the frequency.

Piezoelectric Effect

the ability of certain materials to generate an electric charge in response to applied mechanical stress.

Armstrong

Oscillator that employs a transformer in parallel with a capacitor.

Hartley oscillator

Uses a tapped inductor in parallel with a capacitor.

Colpitts oscillator

Has a capacitor voltage divider

Clapp oscilaltor

an improvement of Colpitts Oscillator. The basic difference is an additional capacitor Cs in series with the inductor in the resonant feedback circuit.

diode

The ____ is a 2-terminal device.

The voltage across the diode is 0 V

The current is infinite

The forward resistance is defined as R_F = V_F / I_F

The diode acts like a short

characteristics of conduction region

All of the voltage is across the diode

The current is 0 A

The reverse resistance is defined as R_R = V_R / I_R

The diode acts like open

characteristics of a non conduction region

Silicon = 0.7V

germanium = 0.3V

gallium arsenide = 1.2V

list of semiconductor materials

doping

The electrical characteristics of silicon and germanium are improved by adding materials in a process called

n-type

____ materials contain an excess of conduction band electrons.

p-type

____ materials contain an excess of valence band holes.

Diode checker

Ohmmeter

Curve tracer

Diodes are commonly tested using one of these types of equipment

Zener diodes

Light-emitting diodes

Diode arrays

There are several types of diodes besides the standard p-n junction diode.  Three of the more common are:

FETs, BJT

____ are voltage controlled devices. ____ are current controlled devices

C) A shorted diode

What does a high resistance reading in both forward- and reverse-bias directions indicate?

A) A good diode B) An open diode

C) A shorted diode D) A defective ohmmeter

 B) negative temperature 

 2. Ge and Si have a(n) _____ coefficient in forward bias.

 A) positive temperature 

 B) negative temperature 

 C) absolute temperature 

 D) temperature free

 C) shrinks

 The depletion width _____ in the forward bias, which results in having a majority flow across the junction.

 A) widens  B) remains unchanged 

 C) shrinks  D) widens and shrinks alternatively

B) exponential 

 The forward characteristics curve of a diode grows in _____ form.

 A) linear  B) exponential 

 C) logarithmic  D) sinusoidal

 A) double

 The reverse saturation current Is will just _____ in magnitude for every 10° C increase in temperature.

 A) double  B) remain the same 

 C) halve  D) triple

 A) reciprocal of the slope

 The ac resistance of a diode is the _____ of the characteristic curve at the Q-point of operation.

 A) reciprocal of the slope  B) slope 

 C) midpoint  D) average value

 C)    Saturation

 In which region are both the collector-base and base-emitter junctions forward-biased?

 A)    Active   B)    Cutoff  

 C)    Saturation   D)    All of the above

 A) Zero amperes

 What is the level of IG in an FET?

 A) Zero amperes  B) Equal to ID 

 C) Depends on VDS  D) Undefined

 C) ohmic

 The region to the left of the pinch-off locus is referred to as the _____ region.

 A) saturation  B) cutoff 

 C) ohmic  D) All of the above

B) parabolic

 The pinch-off voltage continues to drop in a _____ manner as VGS becomes more and more negative.

 A) linear  B) parabolic 

 C) cubic  D) None of the above