Technician Class Series – Electrons – Go With the Flow

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Hello everybody and welcome back to Everything Hamradio! Today we are going to continue our series on the Technician Class License Question Pool! Today we will be talking about the microscopic world of Electrons.

As always, the correct answers will be in bold. I also recommend that you only read the correct answers when studying for your test. If you do this, when you take your test and you see a question, there will be a better chance that the correct answer will jump out at you easier. Some say that this approach is kind of like cheating, but the way that I see it, you will always be learning something in this hobby and you don’t have to know everything there is to know about the hobby to get your license.

If you would like to purchase a copy of the Technician Class study book, written by Gordon West, WB6NOA with Eric P. Nichols, KL7AJ, that this series is loosely based around, below is a link to it.

Let’s move on to the good stuff, shall we?


 

T5A05 What is the electrical term for the electromotive force (EMF) that causes electron flow?

  1. Voltage
  2. Ampere-hours
  3. Capacitance
  4. Inductance

Think of electromotive force as water. When you turn on your faucet, it is like turning on a switch on a circuit. The force of the water is the voltage and the flow of the water is the current.

T5A11 What is the basic unit of electromotive force?

  1. The volt
  2. The watt
  3. The ampere
  4. The ohm

Electromotive Force is also known as voltage. We measure voltage by using a voltmeter to tell us how many volts there are.

Craftsman Digital Multimeter

T7D01 Which instrument would you use to measure electric potential or electromotive force?

  1. An ammeter
  2. A voltmeter
  3. A wavemeter
  4. An ohmmeter

By using a voltmeter, you can measure how much voltage or electromotive force there is in a circuit.

T7D02 What is the correct way to connect a voltmeter to a circuit?

  1. In series with the circuit
  2. In parallel with the circuit
  3. In quadrature with the circuit
  4. In phase with the circuit

You measure voltage by connecting the leads in parallel with the circuit you are measuring.

T6A10 Which of the following battery types is rechargeable?

  1. Nickel-metal hydride
  2. Lithium-ion
  3. Lead-acid gel-cell
  4. All of these choices are correct

Nickel-Metal Hydride(NMh) and Lithium-Ion(Li-Ion) are commonly found in hand-held transceiver batteries. Lead acid gel cell’s are batteries like could be in your car or ATV. Therefore all of the choices are correct.

T6A11 Which of the following battery types is not rechargeable?

  1. Nickel-cadmium
  2. Carbon-zinc
  3. Lead-acid
  4. Lithium-ion

Nickel-Cadmium(Nicad), Lead-Acid and Lithium-Ion are all rechargeable batteries. Carbon-zinc batteries are like Alkaline batteries that you buy at the store. They have the smallest capacity of any battery and are not rechargeable.

T5A06 How much voltage does a mobile transceiver usually require?

  1. About 12 volts
  2. About 30 volts
  3. About 120 volts
  4. About 240 volts

Normally a mobile transceiver requires 12 volts. This is the normal output of pretty much anything on your vehicle unless you take extra steps to step-up the voltage. The alternator normally puts out 13.8v while the vehicle is in motion which is normally within limits on the input voltage of a mobile radio, however, it is still best practice to get your power directly from them battery to have more of a regulated power supply.

T4A11 Where should the negative return connection of a mobile transceiver’s power cable be connected?

  1. At the battery or engine block ground strap
  2. At the antenna mount
  3. To any metal part of the vehicle
  4. Through the transceiver’s mounting bracket

You should always ground your radios as close to the battery as you can, but personally, I wouldn’t use the ground spot where everything else is grounded as it could cause bleed over and could cause issues. However, that being said, the correct answer is at the battery or engine block ground strap.

T5A03 What is the name for the flow of electrons in an electric circuit?

  1. Voltage
  2. Resistance
  3. Capacitance
  4. Current

Like in the example that we talked about in the first question of this section. In the example, we used a water faucet as an example. The force of the water is the voltage and the flow of the water is the current.

Craftsman Digital Multimeter

T7D04 Which instrument is used to measure electric current?

  1. An ohmmeter
  2. A wavemeter
  3. A voltmeter
  4. An ammeter

Current is measure in Amps. To measure amperage you will use an ammeter.

T7D03 How is an ammeter usually connected to a circuit?

  1. In series with the circuit
  2. In parallel with the circuit
  3. In quadrature with the circuit
  4. In phase with the circuit

When measuring current in a circuit, you connect the leads in series with the circuit.

T5A01 Electrical current is measured in which of the following units?

  1. Volts
  2. Watts
  3. Ohms
  4. Amperes

Current is measure in Amperes or Amps for short.

T5A07 Which of the following is a good electrical conductor?

  1. Glass
  2. Wood
  3. Copper
  4. Rubber

Different types of metals are conductors. Of these choices, copper is the only metal. Copper is also one of the best conductors available. Copper is the main conductor used in wiring today. This like coax, your house wiring, and wiring in your car are all examples of copper wiring. In some older houses, they used aluminum wiring but it has a tendency to over heat and catch fire, especially with the power loads that we require now-a-days.

T5A09 What is the name for a current that reverses direction on a regular basis?

  1. Alternating current
  2. Direct current
  3. Circular current
  4. Vertical current

In electrical systems, there are two types of currents, Alternating and Direct. Alternating Current(AC), is what you have in your house or hotels. Alternating current looks like radio waves. The difference is that when the sin wave drops below the center line, the current actually changes directions. In the United States, AC power runs at 60Hz.

Radio Wave

T6D01 Which of the following devices or circuits changes an alternating current into a varying direct current signal?

  1. Transformer
  2. Rectifier
  3. Amplifier
  4. Reflector

Rectifier changes Alternating current, which changes direction into Direct Current which only goes in one direction. A rectifier is one of the main components in a power supply. You plug the power supply into a wall socket in your house, which provides AC power, and transforms it into DC power to power your radios or other ham related gear.

T5A04 What is the name for a current that flows only in one direction?

  1. Alternating current
  2. Direct current
  3. Normal current
  4. Smooth current

Direct current flows only in one direction. It flows from the negative side of your power source, through your circuit and back to the positive side of your power source.

T6B02 What electronic component allows current to flow in only one direction?

  1. Resistor
  2. Fuse
  3. Diode
  4. Driven Element

diode1Diode only allows current to flow in one direction and is what is used in a rectifier. If you look at a diode you will see a stripe on of end of it, the current will not flow into the side with the stripe.

 

T6B09 What are the names of the two electrodes of a diode?

  1. Plus and minus
  2. Source and drain
  3. Anode and cathode
  4. Gate and base

diodeelements

T6B06 How is the cathode lead of a semiconductor diode usually identified?

  1. With the word cathode
  2. With a stripe
  3. With the letter C
  4. All of these choices are correct

The Cathode lead is on the side with the stripe. It is the lead that power will not go into the diode, but will flow out of from the diode.

T6A01 What electrical component is used to oppose the flow of current in a DC circuit?

  1. Inductor
  2. Resistor
  3. Voltmeter
  4. Transformer

 Another word for oppose is to resist. A Resistoropposes or resists the flow of the current therefore making the current drop with each resister.

Craftsman Digital Multimeter

T7D05 What instrument is used to measure resistance?

  1. An oscilloscope
  2. A spectrum analyzer
  3. A noise bridge
  4. An ohmmeter

Resistance is measured in Ohms, named after Georg Simon Ohm. By now, I’m sure you can guess what you use to measure it, if not, well, you use an Ohmmeter.

T6A02 What type of component is often used as an adjustable volume control?

  1. Fixed resistor
  2. Power resistor
  3. Potentiometer
  4. Transformer

Since an adjustable volume control has to very in resistance to increase or decrease the amount of sound coming out of your speakers, you would have to use a variable resister. A Potentiometer is a variable resistor that has a knob that you adjust to increase or decrease the resistance, therefore changing the output voltage coming out of it.

T6A03 What electrical parameter is controlled by a potentiometer?

  1. Inductance
  2. Resistance
  3. Capacitance
  4. Field strength

When you turn the knob on a potentiometer, you change the resistance that it applies to the circuit. With the change in resistance, it changes the voltage coming out of it.

T5A08 Which of the following is a good electrical insulator?

  1. Copper
  2. Glass
  3. Aluminum
  4. Mercury

In this questions opposite, we talked about how metals are good conductors. Of the above choices, the only one that is not a metal is Glass.

T6A06 What type of electrical component stores energy in a magnetic field?

  1. Resistor
  2. Capacitor
  3. Inductor
  4. Diodeinductors

An inductor, also called a coil, choke or reactor, is a passive two-terminal electrical component which resists changes in electric current passing through it. It consists of a conductor such as a wire, usually wound into a coil.

T6A07 What electrical component is usually composed of a coil of wire?

  1. Switch
  2. Capacitor
  3. Diode
  4. Inductor

 

T5C03 What is the ability to store energy in a magnetic field called?

  1. Admittance
  2. Capacitance
  3. Resistance
  4. Inductance

In electromagnetism and electronics, inductance is the property of an electrical conductor by which a change in current flowing through it induces an electromotive force in both the conductor itself and in any nearby conductors by mutual inductance.

T5C04 What is the basic unit of inductance?

  1. The coulomb
  2. The farad
  3. The henry
  4. The ohm

henry is the basic unit of inductance.

T5C12 What is meant by the term impedance?

  1. It is a measure of the opposition to AC current flow in a circuit
  2. It is the inverse of resistance
  3. It is a measure of the Q or Quality Factor of a component
  4. It is a measure of the power handling capability of a component

Much like resistance does to DC, Impedance does to AC.

T5C13 What are the units of impedance?

  1. Volts
  2. Amperes
  3. Coulombs
  4. Ohms

Also like the unit of resistance, the unit of impedance is Ohms as well.

T5C01 What is the ability to store energy in an electric field called?

  1. Inductance
  2. Resistance
  3. Tolerance
  4. Capacitance

The ability to store energy in an Electric Field is called Capacitance.

T5C02 What is the basic unit of capacitance?

  1. The farad
  2. The ohm
  3. The volt
  4. The henry

Capacitance is measured in Farads.

T6A04 What electrical component stores energy in an electric field?

  1. Resistor
  2. Capacitor
  3. Inductor
  4. Diode

Capacitor uses an electric field to store energy. Capacitors are often used as a type of buffer for an AC to DC converter since the wave pattern can be more of a saw tooth wave than a solid DC wave. It stores energy and when the voltage drops below a certain level, it supplements it until the input voltage comes back up.

T6A05 What type of electrical component consists of two or more conductive surfaces separated by an insulator?Types_of_capacitor.svg

  1. Resistor
  2. Potentiometer
  3. Oscillator
  4. Capacitor

Much like the symbols that stand for capacitors, the two lines are the conductive surfaces and the air between is the insulator.

T6A08 What electrical component is used to connect or disconnect electrical circuits?

  1. Magnetron
  2. Switch
  3. Thermistor
  4. All of these choices are correct

A switch turns on or off your circuit, just like the switches in the rooms in your home turns on and off your lights. With the switch turned off, it kills or disconnects the power to the light bulb.

T6A09 What electrical component is used to protect other circuit components from current overloads?

  1. Fuse
  2. Capacitor
  3. Inductor
  4. All of these choices are correct

A Fuse is a component that is designed to isolate the rest of the circuit in case of a surge or short.

T6B03 Which of these components can be used as an electronic switch or amplifier?

  1. Oscillator
  2. Potentiometer
  3. Transistor
  4. Voltmeter

You can use a transistor as a switch because it will send the current through if certain conditions are met.

T6B01 What class of electronic components is capable of using a voltage or current signal to control current flow?

  1. Capacitors
  2. Inductors
  3. Resistors
  4. Transistors

A transistor has three leads to it, an incoming, outgoing and switch leg(basically). The incoming current goes to the transistor and doesn’t continue through it unless whatever the switch leg is set for is met.

T6B05 Which of the following electronic components can amplify signals?

  1. Transistor
  2. Variable resistor
  3. Electrolytic capacitor
  4. Multi-cell batteryNPN_common_emitter_AC.svg

transistor can be used for more than just a switch. It can also be used as an amplifier. The common-emitter amplifier is designed so that a small change in voltage (Vin) changes the small current through the base of the transistor; the transistor’s current amplification combined with the properties of the circuit mean that small swings in Vin produce large changes in Vout. The picture to the right shows a common-emitter amplifier circuit that is commonly used in radio. It can be used to amplify the signal coming into an antenna so that you can receive it on your radio.

T6B12 What is the term that describes a transistor’s ability to amplify a signal?

  1. Gain
  2. Forward resistance
  3. Forward voltage drop
  4. On resistance

Gain is the term that is used to describe a transistor’s ability to amplify a signal.

T6B10 What are the three electrodes of a PNP or NPN transistor?

  1. Emitter, base, and collector
  2. Source, gate, and drain
  3. Cathode, grid, and plate
  4. Cathode, drift cavity, and collector

On a PNP or NPN transistor the electrodes are called Emitter, Base, and Collector. The base is the switching leg of the transistor.

T6B04 Which of the following components can be made of three layers of semiconductor material?

  1. Alternator
  2. Transistor
  3. Triode
  4. Pentagrid converter

A transistor is made up of three layers of semiconductor material. In a PNP transistor, you will have two plates of p-doped semiconductor plates with a N-doped plate in between. A NPN transistor is just the opposite.

T6B08 What does the abbreviation FET stand for?

  1. Field Effect Transistor
  2. Fast Electron Transistor
  3. Free Electron Transition
  4. Field Emission Thickness

FET stands for Field Effect Transistor. The field-effect transistor (FET) is a transistor that uses an electric field to control the shape and hence the electrical conductivity of a channel of one type of charge carrier in a semiconductor material.

T6B11 What at are the three electrodes of a field effect transistor?

  1. Emitter, base, and collector
  2. Source, gate, and drain
  3. Cathode, grid, and plate
  4. Cathode, gate, and anode

All FETs have source, drain, and gate terminals that correspond roughly to the emitter, collector, and base of Bipolar Junction Transistors (BJTs).


So that brings us to the end of this section. This section brought back so many memories from my college days learning about all this stuff. Not sure if that is a good thing or a bad thing though.

Next week we will be talking about Emergencies! Please share my site with your friends and if you have not done so already, please subscribe to my email list to get the latest and quickest notifications of any new post that I publish.  Please Like me on Facebook, and follow me on Twitter, Google+, LinkedIn. Links to all of these can be found under social on the menu.

Thanks for stopping by. If you have any questions or comments about today’s post, please leave them in the comments below or shoot me an email a k5clm@everythinghamradio.com.

Until next time…

73 de Curtis, K5CLM

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