Electronics 2 Review Flashcards

Flashcards based on the provided lecture notes.

Decibel (dB) Calculation

The base of the logarithm used in the standard decibel calculation is 10.

Logarithms in Electronics

Logarithms compress large ranges of values into a smaller, more manageable range in electronics and signal processing.

Negative Decibel Value

A negative decibel value signifies attenuation (reduction in signal strength).

dB in Multi-Stage Amplifiers

In a multi-stage amplifier, dB values can be added to find the total gain.

3 dB Difference in Audio

A difference of 3 dB in audio systems indicates that human hearing is logarithmic.

Lower Critical Frequency - BJT

Capacitors primarily determine the lower critical frequency response in a BJT amplifier circuit.

BJT Amplifier Gain at Low Frequencies

The gain of a BJT amplifier decreases at low frequencies due to increased reactance of coupling and bypass capacitors.

Overall Lower Cutoff Frequency - BJT

The overall lower cutoff frequency is determined by the highest of all individual cutoff frequencies in a BJT amplifier with multiple RC networks.

Importance of Lower Cutoff Frequency

Considering the lower cutoff frequency in amplifier design ensures the desired frequency response for the intended application.

Modifying Cutoff Frequency - BJT

Increase the value of the coupling capacitors to lower the cutoff frequency in a BJT amplifier circuit.

Lower Cutoff Frequency - JFET

Coupling and Bypass Capacitors primarily influence the lower cutoff frequency (fL) in a JFET amplifier.

Coupling Capacitors at Low Frequencies

At very low frequencies, the coupling capacitors act as open circuits on the frequency response of a JFET amplifier.

Source Bypass Capacitor (CS) Role

The source bypass capacitor (CS) affects the lower cutoff frequency in a JFET amplifier regarding its low-frequency response.

JFET Amplifier at 100 Hz

A JFET amplifier with a lower cutoff frequency of 100 Hz will attenuate frequencies below 100 Hz when amplifying audio signals.

JFET Amplifier Design

To amplify signals down to 10 Hz without significant attenuation, select capacitor values such that all lower cutoff frequencies are well below 10 Hz for coupling and bypass capacitors.

High-Frequency Response of BJT

Internal capacitances primarily affect the high-frequency response of a BJT.

BJT Amplifier Gain at High Frequencies

The gain of a BJT amplifier decreases at high frequencies because the reactance of internal capacitances decreases.

Adjusting Cutoff Frequency - BJT

Decreasing junction capacitance should be adjusted to increase the cutoff frequency of a BJT amplifier.

Dominant Critical Frequency - CE Amplifier

The highest of all RC cutoff frequencies in the circuit is the dominant critical frequency in a CE amplifier.

Transistor Size and High-Frequency Response

Increasing transistor size does not improve high-frequency response because larger transistors have higher junction capacitances.

Miller Effect - JFET Amplifier

Cgd (Gate-drain capacitance) in a JFET amplifier is responsible for the Miller effect.

JFET Amplifier Gain at High Frequencies

The gain of a JFET amplifier decreases at higher frequencies due to lower reactance of inter-electrode capacitances.

Miller Effect Influence

The Miller effect reduces input impedance due to amplified capacitance in a JFET amplifier.

Dominant Critical Frequency - JFET Amplifier

The highest of all RC cutoff frequencies in the circuit is the dominant critical frequency in a common-source JFET amplifier.

Reduce Phase Shift

Using smaller transistors would reduce phase shift at critical frequencies.

Cascading Amplifier Stages

The primary purpose of cascading amplifier stages is to improve overall gain and performance.

Cascode Amplifier Configuration

In a cascode amplifier, a Common Emitter transistor configuration is typically used as the input stage.

Cascode Amplifier Preference

A cascode amplifier is preferred in high-frequency applications because it reduces the Miller effect.

Common-Base Transistor Function

The primary function of the common-base transistor in a cascode configuration is to act as a current buffer.

Cascode vs. Cascade Amplifiers

An engineer might choose a cascode amplifier over a cascade amplifier in a high-frequency application because cascode amplifiers have better frequency response.

CMOS Current Mirror Design

Regulated Cascode Current Mirror topology is suitable for designing a high-swing CMOS current mirror with low compliance voltage requirements.

Touch-Sensitive Switch Design

In designing a touch-sensitive switch using a Darlington pair, a metal contact plate is a critical additional component.

CMOS Technology Advantage

The primary advantage of CMOS technology is low power consumption.

MOSFET Current Source Accuracy

Threshold voltage variations due to process mismatches most affect the accuracy of a practical MOSFET-based current source.

CMOS Current Mirror Accuracy

Transistor mismatch due to process variations most affects the accuracy of a high-performance CMOS current mirror.

Bypass Resistor in Darlington Pair

The purpose of a bypass resistor in a Darlington pair is to discharge stored charge during turn-off.

Darlington Pair Unsuitability

A Darlington pair may be unsuitable for high-frequency applications due to slow switching because of parasitic capacitance.

Feedback in Regulated Cascode

The role of feedback in a regulated cascode current mirror is to increase output resistance and improve accuracy.

Component for Current Source

A transistor is commonly used to implement a practical current source.

Transistor in Current Mirrors

A Bipolar Junction Transistor (BJT) type of transistor is commonly used in basic current mirrors.

Negative Feedback Improvement

Negative feedback improves frequency response in a feedback pair circuit by reducing high-frequency distortion.

Voltage Source to Current Source

A Transistor with emitter degeneration resistor configuration can convert a voltage source into a practical current source.

Ideal Current Source Definition

An ideal current source is a device with infinite internal resistance.

Reducing Delay in CMOS

You can reduce the delay in a CMOS circuit design by optimizing critical path delays using logical effort techniques.

CMOS Inverter Logic Gate

A NOT gate logic gate can be implemented using a single CMOS inverter.

Ideal Current Source Load Resistance

If the load resistance of an ideal current source decreases, both current and voltage remain constant.

Negative Feedback Improvement

Stability and linearity characteristic is improved by negative feedback in a feedback pair connection.

Negative Feedback Affect

Negative feedback decreases voltage gain while stabilizing it in a feedback pair circuit.

Compliance Voltage Definition

Compliance voltage in a current mirror is the minimum voltage required for proper operation.

Darlington Pair Replacement

A Darlington pair would replace a single BJT in a high-current relay driver circuit.

Darlington Pair Connections

The emitter of Q1 is connected to the base of Q2 between the two transistors in a Darlington pair.

Minimizing Dynamic Power

Reducing supply voltage (VDD) design approach would best minimize dynamic power consumption in CMOS circuits.

Darlington Pair High Gain

A Darlington pair has exceptionally high current gain because the total gain is the product of individual transistor gains.

Ideal vs. Practical Current Source

Practical sources show small variations in output current due to finite internal resistance when comparing an ideal and practical current source based on their behavior under varying loads.

CMOS Scaling Effects

Scaling down feature sizes in CMOS technology improves transistor speed and integration density.

Primary Function of Current Mirror

To replicate current from one branch to another is the primary function of a current mirror.

MOSFETs in CMOS Circuits

Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) are used in CMOS circuits.

Resistance Performance

Increasing the resistance in the feedback network reduces stability on circuit performance.

Component for Current Source

A Transistor is used to implement a practical current source.

Transistor in Current Mirrors

Bipolar Junction Transistor (BJT) is used in basic current mirrors

Transistor combination in Feedback circuit

One NPN and one PNP transistor is used in a typical feedback pair circuit

Feedback pair connection

Two transistors connected in series with feedback applied is a feedback pair connection?