Full Level: Technical aspects
Full Level: Technical aspects
Part of the official RSGB Full Level question bank, filtered to the Technical aspects syllabus section.
- 104 questions in this section
- Some questions include a reference diagram or circuit image
Before you start, you may want to open the official RSGB reference data sheet (band plans, frequency tables, conversions) — it's allowed for use during the real exam too.
2025-Full3361
The circuit diagram shows an NPN transistor being used as an amplifier. The potential difference across the Base-Emitter junction is 0.6Volt and there is 1V across Re. Which resistor may be used for R1 in order to create the correct transistor bias. You may assume the base current is insignificant.
2025-Full459
A 50Ω dummy load is connected to a transceiver and 100V of RF is noted on transmit. What is the transceiver's output power?
2025-Full7664
What current will be drawn from the battery?
2025-Full7666
There is 6V across the 1kΩ resistor. What is the battery voltage?
2025-Full7667
The 1kΩ resistor is dissipating 2W of heat. What is the dissipation in the 4kΩ resistor?
2025-Full3555
The diagram shows an air spaced capacitor. Sheets of glass are inserted to fill the spaces between the plates. What effect will this have?
2025-Full460
A capacitor can have its capacitance reduced by
2025-Full8026
As the frequency increases from LF to UHF it is likely that for plastic film capacitors
2025-Full4063
You notice the polythene capacitors in the output filter of your HF transmitter get warm when operating on 29MHz but not so on 1.8MHz even though you are running at a higher power since your antenna is less efficient on the lower frequency. This is probably because
2025-Full98
As a general rule, the losses associated with the dielectric of a capacitor
2025-Full7886
A capacitor is marked as 0.1µF 250V. What does the 250V parameter indicate?
2025-Full95
Which of the following factors would be most important in selecting a suitable reservoir capacitor for use in a mains power supply unit?
2025-Full96
Using a capacitor above its breakdown voltage is likely to
2025-Full104
As the current through a coil increases the resultant magnetic field causes an effect that opposes the increase. This is known as the
2025-Full105
The back EMF created when a current changes, is due to the
2025-Full106
Self Inductance is the inductance
2025-Full3689
The switch in the diagram is initially closed and the current is steady. The switch is then opened and a spark is seen to pass between the switch contacts. The reason for this is that the
2025-Full7674
The drawing shows the circuit of a switching transistor controlling the current in the coil of a relay. The base is fed with regular pulses to cause the relay contacts to close. Which circuit will minimise the voltage spikes caused by the the switching?
2025-Full7706
In the case of self-inductance, the magnetic field created by a changing
2025-Full110
An inductor of negligible resistance is inserted in a series circuit comprising a battery and a resistor. Its effect will be to
2025-Full3556
The neon bulb in the figure needs about 65V to cause it to 'strike'. Approximately how long after switch on will it light?
2025-Full3690
A series circuit is made from an inductor, resistor and switch connected to a battery. At the instant the switch is closed there is zero current in the circuit. The reason for this is that the
2025-Full462
A high voltage power supply for a valve transmitter produces about 1500V. The smoothing capacitor is 100µF and the bleeder resistor is 600kΩ. 1 minute after switch-off the PD across the capacitor will be approximately
2025-Full7676
The switch S in the diagram is closed at time t=0. Which graph correctly shows the voltage across the resistor after the switch is closed?
2025-Full7889
The drawing shows part of the circuit of a Morse key. The voltage source and 1kΩ resistor are inside the transmitter and the coil is added externally to slow the rise and fall of the keying waveform. What is the time constant of the keying circuit?
2025-Full118
In constructing an antenna matching circuit, a capacitor with a reactance of about 190Ω at 7MHz is required. The most suitable value of capacitor would be
2025-Full120
The reactance of a 1µH inductor at 16MHz is approximately
2025-Full124
The graph shows the potential differences (PD) in a circuit comprising a resistor and a capacitor connected in series and fed from an AC source.
2025-Full671
The reactance of the inductor in a 14MHz antenna trap is known to be 200Ω. The capacitor required to complete the tuned circuit would need to have a value of approximately
2025-Full127
In the circuit shown, C1 is used as
2025-Full3322
The circuit diagram shows an oscillator. The function of capacitor C relies upon the ability of a capacitor to
2025-Full7679
A 0.1mH ferrite cored coil is fitted on the back of the microphone socket of a transceiver so it is in series with the connection to the circuit board and microphone amplifier. What is its likely purpose?
2025-Full3569
In the circuit shown the RMS voltage between points A and B will be approximately
2025-Full4076
A resistor of 4000Ω and a capacitor of 27pF are connected in series. What is the impedance of the combination at 1.965MHz?
2025-Full758
A 1000Ω resistor is in series with a pure reactance of 1000Ω. What is the approximate impedance of this series circuit?
2025-Full771
A 300Ω resistor and an 8µF capacitor are connected in series to the secondary of a 50 to 1 (50:1) ratio step-down transformer the primary of which is connected to a 250V 50Hz mains supply. What current will flow through the resistor?
2025-Full6015
To digitize an analogue signal within the range 20Hz to 14kHz, which is the lowest sample rate that will capture the signals?
2025-Full6019
An anti-alias filter should be positioned
2025-Full7395
A phenomenon known as aliasing is caused by
2025-Full7645
A software defined receiver is sampling the output of the RF front end amplifier at 80M samples/s. Which filter response should be incorporated in the RF amplifier to avoid aliasing?
2025-Full7401
The process termed a Fast Fourier Transform
2025-Full7686
The top graph is a spectrum analyser plot of a sinewave and a harmonic. Which TWO plots of the same signal in the time domain does the spectrum plot refer to?
2025-Full7864
The Fourier Transform converts
2025-Full7890
The drawing shows the block diagram of a radio receiver and the signals at points between some of the blocks. Which option best describes the function of block 2?
2025-Full159
The mutual inductance of a transformer is
2025-Full166
A transformer has a potential difference of 100V AC applied to its primary, which results in a primary current of 1A. The potential difference measured at the secondary is 20V AC. The secondary current is
2025-Full170
A transformer with 25 turns on the primary and 5 turns on the secondary, has a 1kΩ resistor connected to the secondary. The impedance measured at the primary will be
2025-Full673
The circuit of a transformer balun is shown in the diagram. The primary is connected to 50Ω coaxial cable and the secondary to open wire feeder. An appropriate impedance for the feeder would be
2025-Full774
A half-wave folded dipole antenna is fed by 300Ω impedance twin feeder. It is connected to the transmitter by a transformer balun as shown in the diagram. What impedance does the primary of this present to the transmitter?
2025-Full7761
Filter circuits using inductors normally specify the 'mix' of the ferrite. Why?
2025-Full129
The inductor in a 14MHz antenna trap is 2µH. The capacitor required to complete the tuned circuit would need to have a value of approximately
2025-Full130
You construct a variable frequency oscillator with a 5µH inductor and a capacitor with a range of 5 to 50pF as the tuned circuit. The lowest frequency it will oscillate at is
2025-Full132
A capacitor and inductor in a parallel tuned circuit resonate at 70.3MHz. The resonant frequency will be reduced if
2025-Full144
A quartz crystal
2025-Full147
Which single component exhibits both series and parallel resonance?
2025-Full3573
The circuit shown
2025-Full134
The drawing shows the response curve of a tuned circuit , its Q-factor is
2025-Full150
Components in a tuned circuit may need high voltage and current ratings because
2025-Full691
A parallel tuned circuit has a Q-factor of 80 and is resonant at 10MHz and it is noted that the current in to the circuit is 100µA. An approximate value for the circulating current would be
2025-Full138
The dynamic resistance of an LCR circuit
2025-Full139
Dynamic resistance is an effect associated with
2025-Full300
A zener diode is intended to conduct when the
2025-Full3418
Which of the graphs shown shows the characteristics of a Zener diode? Forward bias is shown to the right.
2025-Full3577
The graph shows the characteristic curve of
2025-Full3983
What current is flowing through the diode shown in the diagram?
2025-Full319
In the field-effect transistor, the 'pinch-off' voltage is the bias required on the
2025-Full3582
In the diagram the potential at point A is reduced. The effect of this will be
2025-Full3585
The circuit shows an n-channel depletion mode FET amplifier. The potential at the gate should be approximately
2025-Full679
The transistor amplifier shown is correctly biased. R2 is 22kΩ. A suitable value for R1 would be about
2025-Full321
The circuit shown has a voltage gain of
2025-Full322
The circuit shown has a voltage gain of
2025-Full323
The circuit shown has a CURRENT gain of
2025-Full324
Which class of amplifier has the lowest distortion?
2025-Full325
Biasing an NPN transistor so that only the positive parts of the signal are amplified is a description of
2025-Full3404
One feature of a transistor amplifier biased in class C is that
2025-Full7635
In order that an oscillator circuit will oscillate, the gain in the transistor amplifier must
2025-Full7738
The voltage gain in a transistor oscillator circuit must be
2025-Full7739
In an oscillator the gain in the transistor amplifier must be
2025-Full7764
In order to maintain oscillations in a transistor oscillator circuit the
2025-Full7765
If the attenuation in the tuned circuit feedback of an oscillator is greater than the gain of the transistor amplifier then
2025-Full7766
An oscillator is utilising its transistor in emitter follower mode. The phase change of the signal in the feedback circuit must be
2025-Full3427
In the regulated power supply circuit shown the output voltage is 24V. The zener diode should have a voltage of
2025-Full350
The reference voltage in a stabilised mains operated power supply is provided by the
2025-Full352
The output voltage of a stabilised mains operated power supply is often controlled by a
2025-Full3595
It is likely that the device marked 'X' in the drawing is
2025-Full3794
The circuit shows a stabilised power supply. The desired output is 13.4V and the resistors R1 and R2 are both 10kΩ. The zener diode should have a voltage of about
2025-Full7767
Which statement is true in respect of a linear power supply?
2025-Full3428
The diode shown in the power supply for a transmitting valve should have a reverse voltage (PIV) of at least
2025-Full344
The rectifier diodes in a mains operated 12V stabilised power supply have failed and must be replaced. Which of the following diodes would be chosen to replace them?
2025-Full347
A simple power supply consists of a transformer feeding a single diode and capacitor in a half wave circuit. The transformer secondary voltage is 20Vrms. The peak inverse voltage across the diode will be about
2025-Full348
A mains power supply consists of a transformer with a single diode and smoothing capacitor on the transformer secondary. The peak inverse voltage (PIV) across the diode will be approximately equal to
2025-Full3593
If the secondary voltage from the transformer is 10V rms the peak inverse voltage rating (PIV) of the diode should be at least
2025-Full4077
A small power supply is shown in the diagram. The diode should be chosen so its reverse voltage rating is at least
2025-Full7002
What type of component is in the box marked X?
2025-Full7682
The control mechanism monitoring the output voltage of a switch mode power supply is typically fed back to the switching circuits via an optical coupler or other non-conducting means. Why?
2025-Full7741
The size of a smoothing capacitor on the output of a switched mode power supply can be much smaller than the equivalent capacitor on a conventional linear supply. Why?
2025-Full7770
A switched mode power supply is more efficient than a linear one because
2025-Full7771
A concern with the use of switched mode power supplies is that
2025-Full7808
A key difference between a switched mode power supply and a linear one is that
2025-Full7759
A LC oscillator has been designed to oscillate at 8 MHz. You are confident of the accuracy of the capacitor but the inductor is 2% low in value. What will be the frequency of oscillation?
2025-Full7884
The drawing shows an FET circuit biased by R1 and R2. R1 is 80kΩ and R2 is 20kΩ. Both resistors are 10% tolerance. The bias voltage might be lower than its design value by a maximum of
2025-Full7966
Identify all the capacitors (if any) where the tolerance on their actual value will have an effect on the lowest frequency which the amplifier shown will handle.
2025-Full7967
Identify all the capacitors (if any) where the tolerance on their actual value will have an effect on the highest frequency which the amplifier shown will handle.
2025-Full8066
The drawing shows a potential divider where R1 is 80kΩ and R2 is 20kΩ. Both resistors are 5% tolerance. What is the maximum deviation of the output voltage from its design value?