Sub Element G7: Practical Circuits Flashcards
What useful feature does a power supply bleeder resistor provide?
It ensures that the filter capacitors are discharged when power is removed
Which of the following components are used in a power supply filter network?
Capacitors and inductors
Which type of rectifier circuit uses two diodes and a center-tapped transformer?
Full-wave
What is an advantage of a half-wave rectifier in a power supply?
Only one diode is required
What portion of the AC cycle is converted to DC by a half-wave rectifier?
180 degrees
What portion of the AC cycle is converted to DC by a full-wave rectifier?
360 degrees
What is the output waveform of an unfiltered full-wave rectifier connected to a resistive load?
A series of DC pulses at twice the frequency of the AC input
Which of the following is an advantage of a switch mode power supply as compared to a linear power supply?
High-frequency operation allows the use of smaller components
What is the reason for neutralizing the final amplifier stage of a transmitter?
To eliminate self-oscillations
Which of these classes of amplifiers has the highest efficiency?
Class C
Which of the following describes the function of a two-input AND gate?
Output is high only when both inputs are high
Which of the following describes the function of a two input NOR gate?
Output is low when either or both inputs are high
How many states does a 3-bit binary counter have?
8
What is a shift register?
A clocked array of circuits that passes data in steps along the array
Which of the following are basic components of a sine wave oscillator?
A filter and an amplifier operating in a feedback loop
How is the efficiency of an RF power amplifier determined?
Divide the RF output power by the DC input power
What determines the frequency of an LC oscillator?
The inductance and capacitance in the tank circuit
Which of the following describes a linear amplifier?
An amplifier in which the output preserves the input waveform
For which of the following modes is a Class C power stage appropriate for amplifying a modulated signal?
FM
Which of the following is used to process signals from the balanced modulator then send them to the mixer in some single sideband phone transmitters?
Filter
Which circuit is used to combine signals from the carrier oscillator and speech amplifier then send the result to the filter in some single sideband phone transmitters?
Balanced modulator
What circuit is used to process signals from the RF amplifier and local oscillator then send the result to the IF filter in a superheterodyne receiver?
Mixer
What circuit is used to combine signals from the IF amplifier and BFO and send the result to the AF amplifier in some single sideband receivers?
Product detector
Which of the following is an advantage of a direct digital synthesizer (DDS)?
Variable frequency with the stability of a crystal oscillator
What should be the impedance of a low-pass filter as compared to the impedance of the transmission line into which it is inserted?
About the same
What is the simplest combination of stages that implement a superheterodyne receiver?
HF oscillator, mixer, detector
What circuit is used in analog FM receivers to convert IF output signals to audio?
Discriminator
What is the phase difference between the I and Q signals that software-defined radio (SDR) equipment uses for modulation and demodulation?
90 degrees
What is an advantage of using I and Q signals in software-defined radios (SDRs)?
All types of modulation can be created with appropriate processing.
What is meant by the term “software-defined radio” (SDR)?
A radio in which most major signal processing functions are performed by software
What is the frequency above which a low-pass filter’s output power is less than half the input power?
Cutoff frequency
What term specifies a filter’s maximum ability to reject signals outside its passband?
Ultimate rejection
The bandwidth of a band-pass filter is measured between what two frequencies?
Upper and lower half-power
What term specifies a filter’s attenuation inside its passband?
Insertion loss
Which of the following is a typical application for a Direct Digital Synthesizer?
A high-stability variable frequency oscillator in a transceiver