1.
In general we expect a circuit composed of common emitter NPN audio transistor amplifier stages to have _______ .
Correct Answer
B. Negative ground
Explanation
In general, a circuit composed of common emitter NPN audio transistor amplifier stages is expected to have a negative ground. This means that the circuit is referenced to a negative voltage potential, with the ground symbol representing the common reference point for all components.
2.
Which statement is true?
Correct Answer
A. When an SCR is triggered at its gate, the SCR keeps on conducting as long as the two other terminals are forward biased.
Explanation
When an SCR (Silicon Controlled Rectifier) is triggered at its gate, it enters into a conducting state and remains conducting as long as the anode and cathode terminals are forward biased. This means that the voltage across the anode and cathode terminals is in the correct polarity for the SCR to continue conducting. If the voltage across these terminals becomes reverse biased or falls below a certain threshold, the SCR will stop conducting. Therefore, the statement "When an SCR is triggered at its gate, the SCR keeps on conducting as long as the two other terminals are forward biased" is true.
3.
The TRIAC (Triode for Alternating Current) is virtually _______.
Correct Answer
D. Two SCRs (silicon controlled rectifiers) back to back
Explanation
The TRIAC is virtually two SCRs (silicon controlled rectifiers) back to back. This means that it can control the flow of current in both directions, allowing it to work with alternating current. This characteristic makes the TRIAC a useful component in applications such as dimmer switches, motor speed control, and AC power control.
4.
Although made obsolete with the invention of the diac, what non-solid state device is a good component to use in triggering SCRs (silicon controlled rectifier) and TRIACs?
Correct Answer
C. Neon lamp
Explanation
A neon lamp is a non-solid state device that can be used to trigger SCRs and TRIACs. When a high voltage is applied to the lamp, it ionizes the gas inside and creates a conducting path. This sudden change in conductivity can be used to trigger the SCRs and TRIACs. Although it has been made obsolete by the invention of the diac, the neon lamp is still a viable option for this purpose.
5.
The closest semiconductor "equivalent" to a vacuum tube triode is ________.
Correct Answer
B. Vacuum tubes
Explanation
The correct answer is Vacuum tubes. Vacuum tubes are the closest semiconductor equivalent to a vacuum tube triode because they operate on the same principle of controlling the flow of electrons through a vacuum. Both vacuum tube triodes and vacuum tubes use a heated cathode to emit electrons and a control grid to modulate the electron flow. This is similar to how a field effect transistor operates, but vacuum tubes are a more direct equivalent to vacuum tube triodes. Solid-state ICs and capacitors are not semiconductors equivalent to vacuum tube triodes.
6.
An important figure of merit for power amplifiers is its gain. A transistor will have its Beta while a triode will have its _______.
Correct Answer
D. Mu
Explanation
In this question, we are asked to identify the figure of merit for a triode. The given options are Ce, Au, Te, and Mu. Among these options, "Mu" is the correct answer. Mu is the figure of merit for a triode, which represents the amplification factor or gain of the device. It is similar to Beta, which represents the gain of a transistor. Therefore, the correct answer is Mu.
7.
The important feature of an NPN common collector transistor is ______.
Correct Answer
B. High input impedance
Explanation
The important feature of an NPN common collector transistor is high input impedance. This means that the transistor has a high resistance to the input signal, allowing it to effectively amplify weak signals without loading the source. This is particularly useful in applications where the input signal is low in amplitude and needs to be boosted for further processing or amplification.
8.
In order to emit light, an L.E.D (light emitting diode) must be _______.
Correct Answer
A. Forward biased
Explanation
An LED must be forward biased in order to emit light. When an LED is forward biased, a voltage is applied in the forward direction across the p-n junction of the diode. This allows current to flow through the diode, causing the electrons and holes to recombine at the junction and release energy in the form of light. Reverse biasing or applying no bias to an LED will not allow the necessary current flow for light emission. The option "abstract cabrillo network biased" is not a valid term and does not provide any meaningful explanation.
9.
The zener diode serves as a good simple voltage reference because it maintains a relatively constant voltage across it when _______.
Correct Answer
C. Reverse biased
Explanation
When a zener diode is reverse biased, it operates in the breakdown region where it maintains a relatively constant voltage across it. This is due to the unique characteristics of the zener diode, which allows it to regulate the voltage by conducting current in the reverse direction when the voltage exceeds the breakdown voltage. Therefore, the zener diode is commonly used as a voltage reference in various electronic circuits.
10.
Large capacitors are used in Power supplies to smoothen the voltage output of bridge diode rectifiers by being wired _______ an inductor at the output of the rectifier.
Correct Answer
A. Parallel to
Explanation
Large capacitors are used in power supplies to smoothen the voltage output of bridge diode rectifiers by being wired in parallel to an inductor at the output of the rectifier. This configuration allows the capacitor to store electrical energy during the peaks of the rectified AC waveform and release it during the troughs, effectively reducing voltage ripple and providing a more stable DC output. By being connected in parallel to the inductor, the capacitor and inductor work together to filter out any fluctuations in the voltage, resulting in a smoother output.
11.
The 1N34A germanium diode is the component of choice when it comes to signal detection or demodulation of AM signals. Silicon diodes are not used for this because ______.
Correct Answer
D. They generally have a higher barrier potential
Explanation
Silicon diodes are not used for signal detection or demodulation of AM signals because they generally have a higher barrier potential. The barrier potential is the voltage required to overcome the potential barrier at the junction of a diode. Silicon diodes have a higher barrier potential compared to germanium diodes, which means that a higher voltage is required for them to conduct and allow the signal to be detected or demodulated. Germanium diodes, on the other hand, have a lower barrier potential, making them more suitable for this purpose.
12.
A diode rectifier configuration which produces a full wave output and requires no center tap in the
transformer secondary winding of a power transformer is _______.
Correct Answer
C. Bridge configuration
Explanation
A bridge configuration diode rectifier produces a full wave output and does not require a center tap in the transformer secondary winding. In this configuration, four diodes are arranged in a bridge formation, allowing the current to flow in both directions through the load. This eliminates the need for a center tap in the transformer, making it a more efficient and cost-effective solution for power rectification.
13.
What is a two terminal device that conducts current easier in only one direction?
Correct Answer
A. Diode
Explanation
A diode is a two-terminal device that conducts current easier in only one direction. It has a p-n junction, which allows current to flow from the anode (positive terminal) to the cathode (negative terminal) when the diode is forward biased. However, when the diode is reverse biased, it blocks the current flow. This property makes diodes useful in rectifying AC to DC, as well as in protecting electronic circuits from reverse current.
14.
When the polarity of voltage is incorrect, the diode acts as a very high resistance that does not allow conduction and is said to be in what condition?
Correct Answer
A. Reverse bias
Explanation
When the polarity of voltage is incorrect, the diode is said to be in reverse bias. In this condition, the diode acts as a very high resistance and does not allow conduction. Reverse bias occurs when the positive terminal of the power supply is connected to the cathode of the diode and the negative terminal is connected to the anode. This causes the diode to block the flow of current and prevents conduction.
15.
What is the type of diode usually made of silicon material and intended for rectification purposes, i.e., converting an alternating current to direct current in DC power supplies?
Correct Answer
C. Rectifier diode
Explanation
A rectifier diode is a type of diode that is made of silicon material and is specifically designed for rectification purposes. It is used to convert an alternating current (AC) to direct current (DC) in DC power supplies. Rectifier diodes have a high current carrying capacity and low forward voltage drop, making them ideal for rectification applications. Germanium diodes, on the other hand, are not commonly used for rectification and have different characteristics compared to silicon diodes. Plastic diodes are not commonly used in rectification applications either. Therefore, the correct answer is rectifier diode.
16.
What is another rectifier device used primarily for demodulation or separating the audio signal from a modulated carrier wave?
Correct Answer
B. Signal Crystal Diode
Explanation
A signal crystal diode is another rectifier device used primarily for demodulation or separating the audio signal from a modulated carrier wave. It is specifically designed to operate at high frequencies and has a low forward voltage drop, making it ideal for this purpose. The crystal diode allows the audio signal to pass through while blocking the carrier wave, effectively separating the two signals. This allows for the extraction of the audio signal from the modulated carrier wave.
17.
When two or more diodes are connected in parallel to increase current handling capacity, what is the purpose of the resistor connected in series with each diode?
Correct Answer
D. To ensure that one diode doesn't carry most of the current
Explanation
The purpose of the resistor connected in series with each diode when two or more diodes are connected in parallel is to ensure that one diode doesn't carry most of the current. By adding the resistor, it helps to distribute the current evenly among the diodes, preventing one diode from taking on a higher load than the others. This ensures that the current handling capacity is shared among all the diodes, increasing their overall efficiency and preventing any individual diode from being overloaded.
18.
What is a p-n device which is like a rectifier diode except that it is usually intended to indicate flow of current, as a power ON indicator or condition of a circuit?
Correct Answer
B. LED
Explanation
LED stands for Light Emitting Diode. It is a p-n device that acts as a rectifier diode but is primarily used to indicate the flow of current. LEDs emit light when current passes through them in the forward direction, making them suitable for power ON indicators or indicating the condition of a circuit. CFL, ITU, and NTC are not p-n devices like rectifier diodes or LEDs, and they do not serve the same purpose.
19.
Like a safety pin on a grenade, what device should always be shunted to a large high voltage electrolytic capacitor when handled by personnel in repairing equipment which has been energized?
Correct Answer
A. Resistor
Explanation
When handling equipment that has been energized, personnel should always shunt a large high voltage electrolytic capacitor with a resistor. This is because the capacitor can store a significant amount of electrical charge even after the equipment has been turned off, which can be dangerous if not discharged properly. By shunting the capacitor with a resistor, it allows the stored charge to dissipate slowly and safely, reducing the risk of electric shock or injury to the personnel.
20.
What will happen to the resistance if the temperature of a resistor is increased?
Correct Answer
D. It will change depending on the resistor's temperature coefficient
Explanation
When the temperature of a resistor is increased, the resistance will change depending on the resistor's temperature coefficient. Different materials have different temperature coefficients, which determine how the resistance of the resistor will change with temperature. Some materials have a positive temperature coefficient, meaning their resistance increases with temperature. Others have a negative temperature coefficient, meaning their resistance decreases with temperature. Therefore, without knowing the specific temperature coefficient of the resistor, it is not possible to determine the exact change in resistance.
21.
Which of the following is a reason not to use wire-wound resistors in an RF circuit?
Correct Answer
B. The resistor's inductance could make circuit performance unpredictable
Explanation
Wire-wound resistors have inherent inductance due to the coiled wire used in their construction. This inductance can interfere with the desired performance of an RF circuit, as it can introduce unwanted impedance and affect the frequency response. Therefore, using wire-wound resistors in an RF circuit can make the circuit's performance unpredictable.
22.
Which of the following describes a thermistor?
Correct Answer
A. A device having a specific change in resistance with temperature variations
Explanation
A thermistor is a device that exhibits a specific change in resistance with temperature variations. As the temperature changes, the resistance of a thermistor either increases or decreases in a predictable and specific manner. This property makes thermistors useful for measuring and controlling temperature in various applications, such as in thermostats, temperature sensors, and temperature compensation circuits.
23.
What is a resistor with a continuously adjustable resistance used for volume or brightness control?
Correct Answer
A. Potentiometer
Explanation
A potentiometer is a resistor with a continuously adjustable resistance that is commonly used for volume or brightness control. It allows for precise control over the level of electrical current flowing through a circuit, thereby adjusting the volume or brightness of a device. By adjusting the position of the potentiometer's wiper, the resistance can be increased or decreased, resulting in the desired level of control. This makes potentiometers ideal for applications where variable resistance is required, such as in audio systems or lighting controls.
24.
What is an electronic component that resist the flow of current in a circuit used to provide bias or voltage drop?
Correct Answer
C. Resistor
Explanation
A resistor is an electronic component that resists the flow of current in a circuit. It is commonly used to provide bias or voltage drop in a circuit. A resistor is designed to have a specific resistance value, which determines the amount of current that can pass through it. By controlling the resistance, a resistor can be used to regulate the flow of current and provide the desired voltage drop in a circuit.
25.
Which of the following components should be added to an existing resistor to increase the resistance?
Correct Answer
A. A resistor in series
Explanation
To increase the resistance in a circuit, a resistor should be added in series with the existing resistor. When resistors are connected in series, their resistances add up. This means that the total resistance in the circuit increases, as the current has to pass through both resistors. Adding a resistor in parallel would actually decrease the total resistance, as the current would have multiple paths to flow through. Similarly, adding a capacitor in series or in parallel with a resistor would not increase the resistance.
26.
In electronics components, capacitors and inductors have reactance. Capacitors do not like a sudden change in _______.
Correct Answer
D. Applied voltage
Explanation
Capacitors do not like a sudden change in applied voltage. This is because capacitors store electrical energy in the form of an electric field between two conductive plates. When the voltage across the capacitor suddenly changes, the electric field needs time to adjust, causing a transient current to flow. This sudden change in voltage can lead to voltage spikes or surges, which can damage the capacitor or other components in the circuit. Therefore, capacitors are designed to smooth out and stabilize voltage changes, making them sensitive to sudden changes in applied voltage.
27.
Large electrolytic DC capacitors have to be wired in circuit observing the proper polarity because a wrong polarity wiring may result in _______.
Correct Answer
A. Production of gases in the electrolyte which can cause an explosion
Explanation
Large electrolytic DC capacitors have to be wired in circuit observing the proper polarity because a wrong polarity wiring may result in production of gases in the electrolyte which can cause an explosion. This is because electrolytic capacitors have a specific electrolyte inside them that can react with the electrodes when a wrong polarity is applied. This reaction can generate gases, such as hydrogen, which can build up pressure and potentially cause an explosion. Therefore, it is crucial to wire these capacitors correctly to ensure safe operation.
28.
The capacitors with the highest voltage ratings for use with high power tuned circuit of a legal limit tube RF amplifier will have a dielectric of ________.
Correct Answer
D. Vacuum
Explanation
The capacitors with the highest voltage ratings for use with a high power tuned circuit of a legal limit tube RF amplifier will have a vacuum dielectric. This is because vacuum capacitors can handle high voltages without breakdown or arcing, making them suitable for high power applications.
29.
What electronic device that is made up of two conductive surfaces that are separated from each other by a dielectric? This dielectric can be any insulating material such as paper, oil, plastic, mica, glass or even air.
Correct Answer
C. Capacitor
Explanation
A capacitor is an electronic device that consists of two conductive surfaces, known as plates, which are separated by a dielectric material. This dielectric can be any insulating material, such as paper, oil, plastic, mica, glass, or even air. When a voltage is applied across the plates, it causes an electric field to form in the dielectric, storing electrical energy. Capacitors are commonly used in electronic circuits for various purposes, such as energy storage, filtering, and coupling. They are essential components in many electronic devices, including computers, televisions, and smartphones.
30.
What capacitors are either electrolytic or tantalum type which are used like battery, i.e, with reference to polarity of terminals?
Correct Answer
B. Polarized
Explanation
Electrolytic and tantalum capacitors are both types of polarized capacitors, meaning they have a positive and a negative terminal. This polarity is important because connecting them the wrong way can cause damage or failure. Unlike non-polarized capacitors, which can be connected in either direction, electrolytic and tantalum capacitors must be connected with the correct polarity to function properly. Therefore, the term "polarized" accurately describes these types of capacitors.
31.
What type of capacitor may be connected either way in a circuit, i.e., without polarity consideration, usually applied in audio and RF circuits and as suppressors?
Correct Answer
A. Fixed non-polarized
Explanation
Fixed non-polarized capacitors can be connected in either direction in a circuit without considering polarity. These capacitors are commonly used in audio and RF circuits as well as suppressors. They are designed to handle both positive and negative voltages without any issues, making them versatile and convenient to use in various applications.
32.
Which of the following is an important characteristic for capacitors used to filter the DC output of a switching power supply?
Correct Answer
C. Low equivalent series resistance
Explanation
Low equivalent series resistance is an important characteristic for capacitors used to filter the DC output of a switching power supply because it helps to minimize the loss of energy and maintain a stable and efficient power supply. A low equivalent series resistance allows the capacitor to effectively filter out any unwanted noise or ripple in the output voltage, ensuring a clean and smooth DC signal. It also helps to reduce power losses and improve the overall performance of the power supply.
33.
Which of the following types of capacitors are often used in power supply circuits to filter the rectified AC?
Correct Answer
D. Electrolytic
Explanation
Electrolytic capacitors are often used in power supply circuits to filter the rectified AC. These capacitors have a high capacitance value and are capable of handling high voltage levels. They are specifically designed for use in power supply applications and are able to withstand the high ripple currents that occur in these circuits. The electrolytic capacitors work by storing and releasing electrical energy, effectively smoothing out the rectified AC waveform and reducing any unwanted noise or ripple.
34.
Which of the following is an advantage of ceramic capacitors as compared to other types of capacitors?
Correct Answer
B. Comparatively low cost
Explanation
Ceramic capacitors have the advantage of being comparatively low cost compared to other types of capacitors. This means that they are more affordable and cost-effective, making them a popular choice in many applications.
35.
Which of the following is an advantage of an electrolytic capacitor?
Correct Answer
C. High capacitance for given volume
Explanation
An advantage of an electrolytic capacitor is that it provides high capacitance for a given volume. This means that it can store a large amount of electrical charge in a small space, making it suitable for applications where space is limited.
36.
While the turns ratio of a transformer is the same as voltage ratio between a primary and secondary windings, the impedance ratio is _______.
Correct Answer
D. The square of the turns ratio
Explanation
The impedance ratio of a transformer is equal to the square of the turns ratio. This means that if the turns ratio is doubled, the impedance ratio will be quadrupled. Similarly, if the turns ratio is tripled, the impedance ratio will be nine times. The square of the turns ratio is used to calculate the impedance ratio because impedance is proportional to the square of the number of turns in a coil.
37.
What device is used in electronic circuits to introduce inductance, frequently found in tuning and filter circuits?
Correct Answer
A. Coil
Explanation
A coil is a device used in electronic circuits to introduce inductance. It is frequently found in tuning and filter circuits. A coil is typically made of conductive metal, such as copper plated wire, which allows for the flow of electric current and the generation of a magnetic field. The inductance created by the coil helps to regulate the flow of current and can be adjusted to specific frequencies in tuning circuits or used to filter out unwanted frequencies in filter circuits.
38.
What is an advantage of using a ferrite core toroidal inductor?
Correct Answer
B. Large values of inductance may be obtained, The magnetic properties of the core may be optimized for a specific range of frequencies, Most of the magnetic field is contained in the core
Explanation
Using a ferrite core toroidal inductor has several advantages. Firstly, it allows for large values of inductance to be obtained. This is beneficial in applications where high inductance is required. Secondly, the magnetic properties of the core can be optimized for a specific range of frequencies, allowing for better performance in that frequency range. Lastly, most of the magnetic field generated by the inductor is contained within the core, reducing interference with other components and improving overall efficiency.
39.
How should the winding axes of solenoid inductors be placed to minimize their mutual inductance?
Correct Answer
A. At right angles
Explanation
The winding axes of solenoid inductors should be placed at right angles to minimize their mutual inductance. This is because when the winding axes are perpendicular to each other, the magnetic fields produced by the currents flowing through the inductors are also perpendicular to each other. As a result, the interaction between the magnetic fields is minimized, reducing the mutual inductance between the inductors.
40.
Why would it be important to minimize the mutual inductance between two inductors?
Correct Answer
D. To reduce unwanted coupling between circuits
Explanation
It is important to minimize the mutual inductance between two inductors in order to reduce unwanted coupling between circuits. Mutual inductance occurs when the magnetic field produced by one inductor induces a voltage in the other inductor, leading to interference and cross-talk between circuits. By minimizing mutual inductance, we can prevent this unwanted coupling and ensure that each circuit operates independently without affecting the performance of the other circuit.
41.
What is an electrical device consisting of two or more coils coupled together by magnetic induction usually converting 220V AC line to a lower secondary winding voltage for DC power supplies?
Correct Answer
A. Transformer
Explanation
A transformer is an electrical device that consists of two or more coils coupled together by magnetic induction. It is commonly used to convert high voltage 220V AC line to a lower secondary winding voltage for DC power supplies. Transformers are essential in electrical systems as they allow for efficient transmission of electrical energy at different voltage levels. They work on the principle of electromagnetic induction, where the primary coil induces a magnetic field in the core, which in turn induces a voltage in the secondary coil. This voltage is then used to power various electrical devices.
42.
Which part of a transformer is normally connected to the incoming source of energy?
Correct Answer
B. The primary
Explanation
The primary coil of a transformer is normally connected to the incoming source of energy. The primary coil is responsible for receiving the electrical energy from the source and transferring it to the secondary coil through electromagnetic induction. This allows for the transformation of voltage levels in the transformer.
43.
Why is impedance matching important?
Correct Answer
A. So the source can deliver maximum power to the load
Explanation
Impedance matching is important because it allows the source to deliver maximum power to the load. When the impedance of the source matches the impedance of the load, it ensures that the maximum amount of power is transferred from the source to the load without any power being reflected back. This maximizes the efficiency of the system and ensures that the load receives the maximum power it requires.
44.
When they were first developed, the chief advantage of CMOS digital circuits over the standard 7400 TTL series digital circuits is ________.
Correct Answer
C. Its lower power consumption
Explanation
The chief advantage of CMOS digital circuits over the standard 7400 TTL series digital circuits is their lower power consumption. CMOS circuits use complementary MOSFETs, which consume very little power when not switching states. This makes them more efficient and suitable for battery-powered devices or applications where power consumption is a concern. In contrast, TTL circuits consume more power due to their use of transistors and resistors. Therefore, CMOS circuits offer the advantage of lower power consumption, making them a preferred choice in many applications.
45.
All quartz crystals used in communications, rely on utilizing the ________.
Correct Answer
D. Piezoelectric effect
Explanation
Quartz crystals used in communications rely on the piezoelectric effect. The piezoelectric effect is the ability of certain materials, like quartz, to generate an electric charge when mechanical stress is applied to them. In the case of quartz crystals, when an electric field is applied to the crystal, it vibrates at a specific frequency. This vibration is used to generate a stable and precise frequency for communication devices. Therefore, the piezoelectric effect is essential for the functioning of quartz crystals in communication technology.
46.
Which of these works on the same principle as a CFL (compact flourescent lamp)?
Correct Answer
A. Neon lamp
Explanation
A neon lamp works on the same principle as a CFL. Both neon lamps and CFLs use gas discharge to produce light. In a neon lamp, the gas inside the lamp is excited by a high voltage, causing it to emit light. Similarly, in a CFL, an electric current is passed through a gas-filled tube, which causes the gas to emit ultraviolet light. The ultraviolet light then interacts with a phosphor coating on the inside of the tube, producing visible light. Therefore, a neon lamp and a CFL operate on the same principle of gas discharge to generate light.
47.
The very popular SANWA 360TR analog multimeter and its various clones utilizes the D'Arsonval-Weston meter movement which is basically ________.
Correct Answer
A. Moving coil system
Explanation
The correct answer is "moving coil system." The SANWA 360TR analog multimeter and its clones use the D'Arsonval-Weston meter movement, which is a type of moving coil system. This system is commonly used in analog meters to measure current, voltage, and resistance. It consists of a coil that moves in a magnetic field, producing a deflection on a scale to indicate the measurement. This design provides accurate and reliable analog readouts, making it a popular choice for multimeters. Additionally, the D'Arsonval-Weston meter movement is not specifically designed to be used as an SWR (Standing Wave Ratio) meter, so the statement "can be also used as SWR meter" is incorrect.
48.
LCD (liquid crsytal display) digital multimeters are fast replacing D'Arsonval Weston analog meter, LCDs feature a sealed glass panel containing a "liquid crystal". The molecules of the liquid crystal are
made to twist so that they can channel light between two polarizing plastic sheets by subjecting them to ______.
Correct Answer
B. An electric field
Explanation
The molecules of the liquid crystal are made to twist and channel light between two polarizing plastic sheets by subjecting them to an electric field. This electric field causes the liquid crystal molecules to align in a specific way, allowing light to pass through and create a clear LCD readout.
49.
Given a low power output transistor stage having a collector impedance of 1250 ohms, what will be the best transformer turns ratio to use to couple it to a 50-ohm antenna?
Correct Answer
C. 5:1
Explanation
The best transformer turns ratio to use to couple the low power output transistor stage to a 50-ohm antenna would be 5:1. This ratio ensures efficient impedance matching between the collector impedance of 1250 ohms and the antenna impedance of 50 ohms. By using a 5:1 turns ratio, the transformer can effectively match the impedance and maximize power transfer between the transistor stage and the antenna.
50.
The simple and lowly neon lamp technology has enjoyed a revival in recent years with the invention of ______.
Correct Answer
A. Plasma television
Explanation
The revival of the simple and lowly neon lamp technology can be attributed to the invention of plasma television. Plasma televisions use neon gas to create the images on the screen, which has led to a renewed interest in neon lamp technology.