ELECTRICITY AND ELECTRONICS TRAINING SERIES. MODULE 7-SOLID-STATE DEVICES AND POWER SUPPLIES

Approximately how many times is the mass of the proton to that of an electron?

1,827

Who invented the photophone?

Alexander Graham Bell

What is often used when it is necessary to block the voltage between one electronic circuit and another, and transfer the signal at the same time?

Amplifier coupling capacitor

What gives an indication of how much the output voltage changes over a range of load resistance values?

Figure of merit

Which band are electrons never found in, but may travel back and forth through it, provided they do not come to rest in the band

Forbidden

How many basic types of filter circuits are there?

Four

Which type of device has two or more diodes arranged so that load current flows in the same direction during each half cycle of the ac supply?

Full-wave rectifier

Which type of material was found to be the most sensitive for use in early radio receivers?

Galena

What is the conversion of an alternating current to a pulsating direct current?

Rectification

What converts the alternating current input signal to a pulsating direct current?

Rectifier

Most power supplies are made up of the following four basic sections: transformer, rectifier, filter, and what else?

Regulator

What is the simplest type of rectifier circuit?

Half-wave rectifier

Basic voltage regulators are classified as one of what two ways?

Series or Shunt

Which material used in communications was found to be the most stable?

Silicon

Which type of device operates by virtue of the movement of electrons within a solid piece of semiconductor material?

Solid -state

What are the three states that matter may be found in?

Solids, liquids, and gases

What is a PN junction that is designed to operate in the reverse- bias breakdown region?

Zener diode

What is the overall charge of N material?

Zero

The MOSFET has a higher input impedance than the JFET (how many megohms)

10 to 100 million

Electrolytic capacitors are available in sizes up to how many microfarads or greater?

10,000

What is an external voltage applied to a PN junction called?

Bias

The input resistance of the SCR is relatively low (approximately how many ohms) and requires a current for triggering?

100

The maximum power output for transistor generally ranges from 30 milliwatts to slightly over how many watts?

100

What is the life expectancy of the LED?

100,000+ hours

In the tunnel diode, the semiconductor materials used in forming a junction are doped to the extent of how many impurity atoms for ten-million semiconductor atoms?

1000

115 volts AC can vary from about 105 volts AC to how many volts AC?

125

Which year did Michael Faraday discover that silver sulfide, a semiconductor, has a negative temperature coefficient?

1883

Which year did Munk A. Rosenshold find that certain materials have rectifying properties?

1885

Which year was the zener effect first proposed by Dr. Carl Zener?

1934

Which year did Leo Esaki discover that if a semiconductor junction diode is heavily doped with impurities then it will have a region of negative resistance?

1958

What is a typical light-to-dark resistance ratio for a photocell?

1:1000

What percent of a half -wave rectifier is the ripple frequency of a full- wave rectifier?

200%

Some SCRs can be switched how many times a second?

25,000

How many distinct types of UJTs are presently in use?

40+

The maximum allowable voltage for a transistor is limited to about 200 volts (but usually how many volts or less)?

50

What temperature is the maximum average forward current usually given at?

77 degrees F

What is the maximum reverse DC voltage that will not cause breakdown called?

DC Blocking voltage

The MOSFET is normally constructed so that it operates in one of what two basic modes?

Depletion or Enhancement

What are two terminal semiconductors of various types that are used in seemingly endless applications?

Diodes

What is the process by which small amounts of selected additives, called impurities, are added to semiconductors to increase their current flow?

Doping

Whose initial work led to the development of zener diode which is frequently used today to regulate power supply voltages at precise levels?

Dr. Carl Zener

What is the amount of energy required by an electron to stay in orbit?

Electron energy level

The chemical activity of an atom is determined by the number of what in its valence shell?

Electrons

Which substance cannot be reduced to a simpler form by chemical means?

Element

What uses voltage to control an electrostatic field within the transistor?

FET

Which type of devices either produce light or use light in their operation?

Optoelectronic

Which type of device is obtained when a section of N-type semiconductor material is joined with a similar section of P -type semiconductor material?

PN Junction

What offers very little resistance to current flow in the forward -bias direction but maximum resistance to current flow when reverse biased?

PN junction diode

What indicates the maximum reverse-bias voltage that may be applied to a diode without causing junction breakdown?

PRV

Arsenic, antimony, bismuth, and phosphorous are all what type of impurities?

Pentavalent

What is a list of all the known elements with the number of electrons in each atom contained?

Periodic table of elements

What is a light-controlled variable resistor?

Photodiode

Which type of device converts light energy into electrical energy?

Photovoltaic cell

What could be designed to work within the ultra-high frequencies used in radar, whereas the electron tube could not?

Point-contact semiconductor diode

What carries a positive charge of electricity equal and opposite to the charge of the electron?

Proton

What is current called that flows in pulses in the same direction?

Pulsating DC

In simple terms, energy is required in definite units to move electrons from one shell to the next higher shell. What are these units called?

Quanta

Which process according to Dr. Zener's theory does electrical breakdown in solid dielectrics occur by?

Quantum-Mechanical tunneling

Which terms are AC voltages normally specified in?

RMS values

What is one of the most important uses of a diode?

Rectification

What functions as a switch that can turn on or off small or large amounts of power?

SCR

Copper-oxide rectifiers are generally used in small-current applications such as AC meter movements or for delivering direct current to circuits requiring not more than how many amperes?

10

LED operating voltage is small, about 1.6 volts forward bias and generally about how many milliamperes?

10

How high can the ratio of varactor capacitance to reverse-bias voltage change be?

10 to 1

What is the smallest particle into which an element can be broken down and still retain all its original properties?

Atom

What is the electrostatic field called that is created by the positive and negative ions in the depletion region?

Barrier

What is the most basic type of power supply filter?

Capacitor filter

What provides two equal voltages to the conventional full-wave rectifier?

Center-tapped transformer

What is a chemical combination of two or more elements called?

Compound

What is a band in which the energy level of the electrons is high enough that the electrons will move easily under the influence of an external field?

Conduction

What is a material in which the forbidden gap is so narrow that it can be considered nonexistent?

Conductor

What are solid materials called that have many electrons in the conduction band?

Conductors

There are many known metal-semiconductor combinations that can be used for contact rectification. Which devices are by far the most popular?

Copper oxide and selenium

What is a solid whose atoms or molecules are arranged in a three- dimensional geometrical pattern commonly referred to as a lattice called?

Crystal

What are materials in which the forbidden gap is so large that practically no electrons can be given enough energy to cross the gap?

Insulators

What is a minute piece of semiconductor material that can produce complete electronic circuit functions?

Integrated circuit

In which process does an atom lose or gain electrons?

Ionization

What are two of the most widely known semiconductors that are in use today?

Junction diode and the Transistor

What is one of the most commonly used filters primarily used in radio receivers,small audio amplifier power supplies, and in any type of power supply where the output current is low and the load current is relatively constant?

LC capacitor-input filter

Which type of filter is primarily used in power supplies where voltage regulation is important and where the output current is relatively high and subject to varying load conditions?

LC choke-input

What is any device that draws current defined as?

Load

What is a solid that contains a forbidden gap

Semiconductor

What is anything that occupies space and has weight known as?

Matter

Which two parts is the universe, as we know it today, divided into?

Matter and energy

What is the maximum current called that is permitted to flow in the forward direction in the form of nonrecurring pulses?

Maximum surge current

What is the smallest part of a compound called which has all the characteristics of the compound?

Molecule

What is the most important and most widely used characteristic of the tunnel diode?

Negative resistance region

What has a mass approximately equal to that of a proton but has no electrical charge?

Neutron

What can be used to check a varactor diode in a circuit

Ohmmeter

What is the most convenient and quickest way of testing a diode?

Ohmmeter

What is defined as the time it takes a capacitor to charge to 63.2 percent of the applied voltage or to discharge to 36.8 percent of its total charge?

One time constant

Transistors are semiconductor devices with how many or more terminals?

Three

What steps up or steps down the input line voltage and isolates the power supply from the power line?

Transformer

Aluminum, indium, gallium, and boron are all what type of impurities?

Trivalent

The conduction band along with which other band are the two energy bands that an electron can exist in?

Valence

What is a band in which the energy level is the same as the valence electrons of the atoms?

Valence

What is an atom's ability to combine with other atoms called?

Valence

What is the outer shell of an atom called?

Valence shell

Which type of diode behaves like a variable capacitor, with the PN junction functioning like the dielectric and plates of a common capacitor?

Varactor

What is the most widespread use of Zener diodes?

Voltage regulators