1. Basic Electricity Two Laws
Technician License Course Module Three Radio and Electronics Fundamentals
Basic Electricity
Two Laws

2. Fundamentals of Electricity
When dealing with electricity what we are referring to is the flow of electrons through a conductor
Electrons are negatively charged atomic particles
The opposite charge is the positive charge
A conductor is a material that allows electrons to move with relative freedom within the material
You need to take some time to make sure all the students are on the same page when dealing with electronics fundamentals. You will probably find a wide range of knowledge from those who have no clue what you’re talking about to those who know far more about the topic as you do. Acknowledge this right up front, but tell the students you are going to lay the vocabulary foundation for material that follows. For those with little knowledge, tell them to hang on because it will become clear as the lesson proceeds, for those more knowledgeable, tell them to be patient and allow for a little instructor license to over simplify so that all can understand.
Point out that the opposite of a conductor is an insulator that does not allow for the free movement of electrons. As an aside, there are materials that under some conditions act as conductors and under other conditions act as insulators…these materials are semi-conductors, the basic materials of today’s solid state technology. 2

3. Fundamentals of Electricity
In electronics and radio, we control the flow of electrons to make things happen
You need to have a basic understanding of how and why we control the flow of electrons so that you can better operate your radio
Use this time to provide some motivation of “why do I need to know this stuff.” 3

4. Conductors & Insulators
Conductors allow electrons to flow
Copper, silver, gold
Insulators impede the flow of electrons
Rubber, glass
Use this time to provide some motivation of “why do I need to know this stuff.” 4

5. Basic Characteristics of Electricity
There are three characteristics to electricity
Voltage
Current
Resistance
All three must be present for electrons to flow

6. Basic Characteristics of Electricity
The flow of water through a hose is a good analogy to understand the three characteristics of electricity and how they are related
Take some time to talk the students through the water analogy. Pressure that pushes water through a hose, in electricity is voltage (or Electromotive force). The water in the hose, in electricity is the electrons (current) that will move. The friction that prevents the water from just freely moving through the hose, in electricity is resistance. Resistance comes from the electrons running into obstacles within the conductor (and other electrons) as they pass through. Have the student rub their hands together and observe what happens (heat). When resistance impedes the flow of electronics (slows the flow down), the change in kinetic energy (energy of movement) must be turned into some form of energy (remember energy is neither created or destroyed, it is just turned into something else) in this case heat. 6

7. Characteristics of Electricity are Interelated
Voltage, current, and resistance must be present to have current flow
Just like water flowing through a hose, changes in voltage, current, and resistance affect each other
That effect is mathematically expressed in Ohm’s Law
If there is no push (voltage) there is no current (current by definition is flowing electrons), if there is no movement, there can be no resistance.
If there is nothing to push, there will be no pressure, no movement-no resistance.
There is always going to be some form of impediment to movement.
What you are describing here is that inter-relationship which is Ohm’s law 7

8. E I R Ohm’s Law E is voltage I is current R is resistance R=E/I I=E/R
Units-volts
I is current
Units-ampere
R is resistance
Units-ohms
R=E/I
I=E/R
E=I x R E I R
Go over the simple Ohm’s Law math and provide a few examples of how to solve problems. Give some homework problems that are the same as test questions (without telling them that they are test questions). Have the students solve these problems so they are confident that they can do the math 8

9. Moving Electrons Doing Something Useful
Anytime energy is expended to do something - work is performed
When moving electrons do some work, power is consumed
Power is measured in the units of Watts
Discuss the concept of power in electronics. Student will probably be familiar with this concept because of their electric bill. 9

10. Power Formula
Power is defined as the amount of current that is being pushed through a conductor or device to do work
P = I x E
E = P/I
I = P/E P
Go through some simple problems using the power formula. Again use test question examples for homework. I E 10

11. Two Basic Kinds of Current
When current flows in only one direction, it is called Direct Current (DC)
Batteries are a common source of DC
Most electronic devices are powered by DC
When current flows alternatively in one direction then in the opposite direction, it is called Alternating Current (AC)
Your household current is AC
Discuss the two different kinds of current and what they might be used for. Point out to the students that their household AC current is frequently converted into DC to run many household appliances. That conversion is done inside the appliance or inside an external converter like a wall-wart.
Explain why house current is AC (easier to transmit the electricity from the power plant to the home) 11

12. VEC Question Pool
Module Three

13. T5A01 Electrical current is measured in which of the following units?
A. Volts
B. Watts
C. Ohms
D. Amperes

14. T5A01 (D)
Electrical current is measured in which of the following units?
A. Volts
B. Watts
C. Ohms
D. Amperes

15. T5A02 Electrical power is measured in which of the following units?
A. Volts
B. Watts
C. Ohms
D. Amperes

16. T5A02 (B)
Electrical power is measured in which of the following units?
A. Volts
B. Watts
C. Ohms
D. Amperes

17. T5A03
What is the name for the flow of electrons in an electric circuit?
A. Voltage
B. Resistance
C. Capacitance
D. Current

18. T5A03 (D)
What is the name for the flow of electrons in an electric circuit?
A. Voltage
B. Resistance
C. Capacitance
D. Current

19. T5A04 What is the name for a current that flows only in one direction?
A. Alternating current
B. Direct current
C. Normal current
D. Smooth current

20. T5A04 (B)
What is the name for a current that flows only in one direction?
A. Alternating current
B. Direct current
C. Normal current
D. Smooth current

21. T5A05
What is the electrical term for the electromotive force (EMF) that causes electron flow?
A. Voltage
B. Ampere-hours
C. Capacitance
D. Inductance

22. T5A05 (A)
What is the electrical term for the electromotive force (EMF) that causes electron flow?
A. Voltage
B. Ampere-hours
C. Capacitance
D. Inductance

23. T5A06 How much voltage does a mobile transceiver usually require?
A. About 12 volts
B. About 30 volts
C. About 120 volts
D. About 240 volts

24. T5A06 (A) How much voltage does a mobile transceiver usually require?
A. About 12 volts
B. About 30 volts
C. About 120 volts
D. About 240 volts

25. T5A07 Which of the following is a good electrical conductor? A. Glass
B. Wood
C. Copper
D. Rubber

26. T5A07 (C) Which of the following is a good electrical conductor?
A. Glass
B. Wood
C. Copper
D. Rubber

27. T5A08 Which of the following is a good electrical insulator? A. Copper
B. Glass
C. Aluminum
D. Mercury

28. T5A08 (B) Which of the following is a good electrical insulator?
A. Copper
B. Glass
C. Aluminum
D. Mercury

29. T5A09
What is the name for a current that reverses direction on a regular basis?
A. Alternating current
B. Direct current
C. Circular current
D. Vertical current

30. T5A09 (A)
What is the name for a current that reverses direction on a regular basis?
A. Alternating current
B. Direct current
C. Circular current
D. Vertical current

31. T5A10
Which term describes the rate at which electrical energy is used?
A. Resistance
B. Current
C. Power
D. Voltage

32. T5A10 (C)
Which term describes the rate at which electrical energy is used?
A. Resistance
B. Current
C. Power
D. Voltage

33. T5A11 What is the basic unit of electromotive force? A. The volt
B. The watt
C. The ampere
D. The ohm

34. T5A11 (A) What is the basic unit of electromotive force? A. The volt
B. The watt
C. The ampere
D. The ohm

35. T5C08
What is the formula used to calculate electrical power in a DC circuit?
A. Power (P) equals voltage (E) multiplied by current (I)
B. Power (P) equals voltage (E) divided by current (I)
C. Power (P) equals voltage (E) minus current (I)
D. Power (P) equals voltage (E) plus current (I)

36. T5C08 (A)
What is the formula used to calculate electrical power in a DC circuit?
A. Power (P) equals voltage (E) multiplied by current (I)
B. Power (P) equals voltage (E) divided by current (I)
C. Power (P) equals voltage (E) minus current (I)
D. Power (P) equals voltage (E) plus current (I)

37. T5C09
How much power is being used in a circuit when the applied voltage is 13.8 volts DC and the current is 10 amperes?
A. 138 watts
B. 0.7 watts
C watts
D. 3.8 watts

38. T5C09 (A)
How much power is being used in a circuit when the applied voltage is 13.8 volts DC and the current is 10 amperes?
A. 138 watts
B. 0.7 watts
C watts
D. 3.8 watts

39. T5C10
How much power is being used in a circuit when the applied voltage is 12 volts DC and the current is 2.5 amperes?
A. 4.8 watts
B. 30 watts
C watts
D watts

40. T5C10 (B)
How much power is being used in a circuit when the applied voltage is 12 volts DC and the current is 2.5 amperes?
A. 4.8 watts
B. 30 watts
C watts
D watts

41. T5C11
How many amperes are flowing in a circuit when the applied voltage is 12 volts DC and the load is 120 watts?
A. 0.1 amperes
B. 10 amperes
C. 12 amperes
D. 132 amperes

42. T5C11 (B)
How many amperes are flowing in a circuit when the applied voltage is 12 volts DC and the load is 120 watts?
A. 0.1 amperes
B. 10 amperes
C. 12 amperes
D. 132 amperes

43. T5D01 What formula is used to calculate current in a circuit?
A. Current (I) equals voltage (E) multiplied by resistance (R)
B. Current (I) equals voltage (E) divided by resistance (R)
C. Current (I) equals voltage (E) added to resistance (R)
D. Current (I) equals voltage (E) minus resistance (R)

44. T5D01 (B) What formula is used to calculate current in a circuit?
A. Current (I) equals voltage (E) multiplied by resistance (R)
B. Current (I) equals voltage (E) divided by resistance (R)
C. Current (I) equals voltage (E) added to resistance (R)
D. Current (I) equals voltage (E) minus resistance (R)

45. T5D02 What formula is used to calculate voltage in a circuit?
A. Voltage (E) equals current (I) multiplied by resistance (R)
B. Voltage (E) equals current (I) divided by resistance (R)
C. Voltage (E) equals current (I) added to resistance (R)
D. Voltage (E) equals current (I) minus resistance (R)

46. T5D02 (A) What formula is used to calculate voltage in a circuit?
A. Voltage (E) equals current (I) multiplied by resistance (R)
B. Voltage (E) equals current (I) divided by resistance (R)
C. Voltage (E) equals current (I) added to resistance (R)
D. Voltage (E) equals current (I) minus resistance (R)

47. T5D03 What formula is used to calculate resistance in a circuit?
A. Resistance (R) equals voltage (E) multiplied by current (I)
B. Resistance (R) equals voltage (E) divided by current (I)
C. Resistance (R) equals voltage (E) added to current (I)
D. Resistance (R) equals voltage (E) minus current (I)

48. T5D03 (B) What formula is used to calculate resistance in a circuit?
A. Resistance (R) equals voltage (E) multiplied by current (I)
B. Resistance (R) equals voltage (E) divided by current (I)
C. Resistance (R) equals voltage (E) added to current (I)
D. Resistance (R) equals voltage (E) minus current (I)

49. T5D04
What is the resistance of a circuit in which a current of 3 amperes flows through a resistor connected to 90 volts?
A. 3 ohms
B. 30 ohms
C. 93 ohms
D. 270 ohms

50. T5D04 (B)
What is the resistance of a circuit in which a current of 3 amperes flows through a resistor connected to 90 volts?
A. 3 ohms
B. 30 ohms
C. 93 ohms
D. 270 ohms

51. T5D05
What is the resistance in a circuit for which the applied voltage is 12 volts and the current flow is 1.5 amperes?
A. 18 ohms
B ohms
C. 8 ohms
D ohms

52. T5D05 (C)
What is the resistance in a circuit for which the applied voltage is 12 volts and the current flow is 1.5 amperes?
A. 18 ohms
B ohms
C. 8 ohms
D ohms

53. T5D06
What is the resistance of a circuit that draws 4 amperes from a 12-volt source?
A. 3 ohms
B. 16 ohms
C. 48 ohms
D. 8 Ohms

54. T5D06 (A)
What is the resistance of a circuit that draws 4 amperes from a 12-volt source?
A. 3 ohms
B. 16 ohms
C. 48 ohms
D. 8 Ohms

55. T5D07
What is the current flow in a circuit with an applied voltage of 120 volts and a resistance of 80 ohms?
A amperes
B. 200 amperes
C amperes
D. 1.5 amperes

56. T5D07 (D)
What is the current flow in a circuit with an applied voltage of 120 volts and a resistance of 80 ohms?
A amperes
B. 200 amperes
C amperes
D. 1.5 amperes

57. T5D08
What is the current flowing through a 100- ohm resistor connected across 200 volts?
A. 20,000 amperes
B. 0.5 amperes
C. 2 amperes
D. 100 amperes

58. T5D08 (C)
What is the current flowing through a 100- ohm resistor connected across 200 volts?
A. 20,000 amperes
B. 0.5 amperes
C. 2 amperes
D. 100 amperes

59. T5D09
What is the current flowing through a 24- ohm resistor connected across 240 volts?
A. 24,000 amperes
B. 0.1 amperes
C. 10 amperes
D. 216 amperes

60. T5D09 (C)
What is the current flowing through a 24- ohm resistor connected across 240 volts?
A. 24,000 amperes
B. 0.1 amperes
C. 10 amperes
D. 216 amperes

61. T5D10
What is the voltage across a 2-ohm resistor if a current of 0.5 amperes flows through it?
A. 1 volt
B volts
C. 2.5 volts
D. 1.5 volts

62. T5D10 (A)
What is the voltage across a 2-ohm resistor if a current of 0.5 amperes flows through it?
A. 1 volt
B volts
C. 2.5 volts
D. 1.5 volts

63. T5D11
What is the voltage across a 10-ohm resistor if a current of 1 ampere flows through it?
A. 1 volt
B. 10 volts
C. 11 volts
D. 9 volts

64. T5D11 (B)
What is the voltage across a 10-ohm resistor if a current of 1 ampere flows through it?
A. 1 volt
B. 10 volts
C. 11 volts
D. 9 volts

65. T5D12
What is the voltage across a 10-ohm resistor if a current of 2 amperes flows through it?
A. 8 volts
B. 0.2 volts
C. 12 volts
D. 20 volts

66. T5D12 (D)
What is the voltage across a 10-ohm resistor if a current of 2 amperes flows through it?
A. 8 volts
B. 0.2 volts
C. 12 volts
D. 20 volts

67. End
Module Three