RIC-8 - Advanced Qualification Question Bank for Amateur Radio Operator Certificate

A-004-01-01 (3)
For the same transformer secondary voltage, which rectifier has the highest average output voltage?

• Half-wave
• Quarter-wave
• Bridge
• Full-wave

A-004-01-02 (2)
In a half-wave power supply with a capacitor input filter and a load drawing little or no current, the peak inverse voltage (PIV) across the diode can reach ________ times the RMS voltage.

• 0.45
• 2.8
• 5.6
• l.4

A-004-01-03 (2)
In a full-wave centre-tap power supply, regardless of load conditions, the peak inverse voltage (PIV) will be ________ times the RMS voltage:

• 0.636
• 2.8
• 0.707
• 1.4

A-004-01-04 (3)
A full-wave bridge rectifier circuit makes use of both halves of the AC cycle, but unlike the full-wave centre-tap rectifier circuit it does not require:

• any output filtering
• a centre-tapped primary on the transformer
• a centre-tapped secondary on the transformer
• diodes across each leg of the transformer

A-004-01-05 (3)
The output from a full-wave bridge rectifier circuit will appear to be:

• double that of the full-wave centre-tap rectifier
• half that of the full-wave centre-tap rectifier
• the same as the full-wave centre-tap rectifier
• the same as the half-wave rectifier

A-004-01-06 (1)
The ripple frequency produced by a fullwave power supply connected to a normal household circuit is:

• l20 Hz
• 60 Hz
• 90 Hz
• 30 Hz

A-004-01-07 (2)
The ripple frequency produced by a halfwave power supply connected to a normal household circuit is:

• 90 Hz
• 60 Hz
• l20 Hz
• 30 Hz

A-004-01-08 (3)
Full-wave voltage doublers:

• create four times the half-wave voltage output
• use less power than half-wave doublers
• use both halves of an AC wave
• are used only in high-frequency power supplies

A-004-01-09 (4)
What are the two major ratings that must not be exceeded for silicon-diode rectifiers used in power-supply circuits?

• Average power; average voltage
• Capacitive reactance; avalanche voltage
• Peak load impedance; peak voltage
• Peak inverse voltage; average forward current

A-004-01-10 (2)
Why should a resistor and capacitor be wired in parallel with power-supply rectifier diodes?

• To smooth the output waveform
• To equalize voltage drops and guard against transient voltage spikes
• To decrease the output voltage
• To ensure that the current through each diode is about the same

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A-004-01-11 (3)
What is the output waveform of an unfiltered full-wave rectifier connected to a resistive load?

• A steady DC voltage
• A sine wave at half the frequency of the AC input
• A series of pulses at twice the frequency of the AC input
• A series of pulses at the same frequency as the AC input

A-004-02-01 (4)
Filter chokes are rated according to:

• reactance at 1000 Hz
• power loss
• breakdown voltage
• inductance and current-handling capacity

A-004-02-02 (3)
Which of the following circuits gives the best regulation, under similar load conditions?

• A half-wave bridge rectifier with a capacitor input filter
• A half-wave rectifier with a choke input filter
• A full-wave rectifier with a choke input filter
• A full-wave rectifier with a capacitor input filter

A-004-02-03 (4)
The advantage of the capacitor input filter over the choke input filter is:

• better filtering action or smaller ripple voltage
• improved voltage regulation
• lower peak rectifier currents
• a higher terminal voltage output

A-004-02-04 (1)
With a normal load, the choke input filter will give the:

• best regulated output
• greatest percentage of ripple
• greatest ripple frequency
• highest output voltage

A-004-02-05 (2)
There are two types of filters in general use in a power supply. They are called:

• choke output and capacitor output
• choke input and capacitor input
• choke input and capacitor output
• choke output and capacitor input

A-004-02-06 (1)
The main function of the bleeder resistor in a power supply is to provide a discharge path for the capacitor in the power supply. But it may also be used for a secondary function, which is to:

• improve voltage regulation
• provide a ground return for the transformer
• inhibit the flow of current through the supply
• act as a secondary smoothing device in conjunction with the filter

A-004-02-07 (1)
In a power supply, series chokes will:

• readily pass the DC but will impede the flow of the AC component
• readily pass the DC and the AC component
• impede the passage of DC but will pass the AC component
• impede both DC and AC

A-004-02-08 (4)
When using a choke input filter, a minimum current should be drawn all the time when the device is switched on. This can be accomplished by:

• utilizing a full-wave bridge rectifier circuit
• placing an ammeter in the output circuit
• increasing the value of the output capacitor
• adjusting the bleeder resistance

A-004-02-09 (3)
In the design of a power supply, the designer must be careful of resonance effects because the ripple voltage could build up to a high value. The components that must be carefully selected are:

• the bleeder resistor and the first choke
• first capacitor and second capacitor
• first choke and first capacitor
• first choke and second capacitor

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A-004-02-10 (3)
Excessive rectifier peak current and abnormally high peak inverse voltages can be caused in a power supply by the filter forming a:

• short circuit across the bleeder
• parallel resonant circuit with the first choke and second capacitor
• series resonant circuit with the first choke and first capacitor
• tuned inductance in the filter choke

A-004-02-11 (3)
In a properly designed choke input filter power supply, the filter capacitor will be about nine-tenths of the AC RMS noload voltage across the voltage; yet it is advisable to use capacitors rated at the peak transformer voltage. Why is this large safety margin suggested?

• Resonance can be set up in the filter producing high voltages
• Under heavy load, high currents and voltages are produced
• Under no-load conditions and a burnedout bleeder, voltages could reach the peak transformer voltage
• Under no-load conditions, the current could reach a high level

A-004-03-01 (1)
What is one characteristic of a linear electronic voltage regulator?

• The conduction of a control element is varied in direct proportion to the line voltage or load current
• It has a ramp voltage at its output
• A pass transistor switches from its "on" state to its "off" state
• The control device is switched on or off, with the duty cycle proportional to the line or load conditions

A-004-03-02 (1)
What is one characteristic of a switching voltage regulator?

• The control device is switched on and off, with the duty cycle proportional to the line or load conditions
• The conduction of a control element is varied in direct proportion to the line voltage or load current
• It provides more than one output voltage
• It gives a ramp voltage at its output

A-004-03-03 (4)
What device is typically used as a stable reference voltage in a linear voltage regulator?

• An SCR
• A varactor diode
• A junction diode
• A zener diode

A-004-03-04 (4)
What type of linear regulator is used in applications requiring efficient utilization of the primary power source?

• A shunt regulator
• A constant current source
• A shunt current source
• A series regulator

A-004-03-05 (3)
What type of linear voltage regulator is used in applications requiring a constant load on the unregulated voltage source?

• A constant current source
• A shunt current source
• A shunt regulator
• A series regulator

A-004-03-06 (3)
How is remote sensing accomplished in a linear voltage regulator?

• An error amplifier compares the input voltage to the reference voltage
• A load connection is made outside the feedback loop
• A feedback connection to an error amplifier is made directly to the load
• By wireless inductive loops

A-004-03-07 (2)
What is a three-terminal regulator?

• A regulator that supplies three voltages at a constant current
• A regulator containing a voltage reference, error amplifier, sensing resistors and transistors, and a pass element
• A regulator containing three error amplifiers and sensing transistors
• A regulator that supplies three voltages with variable current

A-004-03-08 (2)
What are the important characteristics of a three-terminal regulator?

• Maximum and minimum input voltage, minimum output current and maximum output voltage
• Maximum and minimum input voltage, maximum output current and voltage
• Maximum and minimum input voltage, minimum output voltage and maximum output current
• Maximum and minimum input voltage, minimum output current and voltage

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A-004-03-09 (2)
What type of voltage regulator contains a voltage reference, error amplifier, sensing resistors and transistors, and a pass element in one package?

• An op-amp regulator
• A three-terminal regulator
• A switching regulator
• A zener regulator

A-004-03-10 (1)
When extremely low ripple is required, or when the voltage supplied to the load must remain constant under conditions of large fluctuations of current and line voltage, a closed-loop amplifier is used to regulate the power supply. There are two main categories of electronic regulators. They are:

• linear and switching
• non-linear and switching
• linear and non-linear
• "stiff" and switching

A-004-03-11 (2)
A modern type of regulator, which features a reference, high-gain amplifier, temperature-compensated voltage sensing resistors and transistors as well as a pass-element is commonly referred to as a:

• nine-pin terminal regulator
• three-terminal regulator
• twenty-four pin terminal regulator
• six-terminal regulator

A-004-04-01 (2)
In a series-regulated power supply, the power dissipation of the pass transistor is:

• the inverse of the load current and the input/output voltage differential
• directly proportional to the load current and the input/output voltage differential
• dependent upon the peak inverse voltage appearing across the Zener diode
• indirectly proportional to the load voltage and the input/output voltage differential

A-004-04-02 (1)
In any regulated power supply, the output is cleanest and the regulation is best:

• at the point where the sampling network or error amplifier is connected
• across the secondary of the pass transistor
• across the load
• at the output of the pass transistor

A-004-04-03 (1)
When discussing a power supply the ________ resistance is equal to the output voltage divided by the total current drawn, including the current drawn by the bleeder resistor:

• load
• ideal
• rectifier
• differential

A-004-04-04 (3)
The regulation of long-term changes in the load resistance of a power supply is called:

• active regulation
• analog regulation
• static regulation
• dynamic regulation

A-004-04-05 (1)
The regulation of short-term changes in the load resistance of a power supply is called:

• dynamic regulation
• static regulation
• analog regulation
• active regulation

A-004-04-06 (3)
The dynamic regulation of a power supply is improved by increasing the value of :

• the choke
• the input capacitor
• the output capacitor
• the bleeder resistor

A-004-04-07 (4)
The output capacitor, in a power supply filter used to provide power for an SSB or CW transmitter, will give better dynamic regulation if:

• the negative terminal of the electrolytic is connected to the positive and the positive terminal to ground
• a battery is placed in series with the output capacitor
• it is placed in series with other capacitors
• the output capacitance is increased

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A-004-04-08 (3)
In a regulated power supply, four diodes connected together in a Bridge act as:

• equalization across the transformer
• matching between the secondary of the
• power transformer and the filter a rectifier
• a tuning network

A-004-04-09 (3)
In a regulated power supply, components that conduct alternating current at the input before the transformer and direct current before the output are:

• capacitors
• diodes
• fuses
• chokes

A-004-04-10 (1)
In a regulated power supply, the output of the electrolytic filter capacitor is connected to the:

• voltage regulator
• pi filter
• solid-state by-pass circuit
• matching circuit for the load

A-004-04-11 (4)
In a regulated power supply, a diode connected across the input and output terminals of a regulator is used to:

• provide an RF by-pass for the voltage control
• provide additional capacity
• protect the regulator from voltage fluctuations in the primary of the transformer
• protect the regulator