Lesson 6: Current, Voltage, and Resistance in a Circuit
What is the correct current value if the selector is in the 0.5 DCmA position?
0.14 mA
What is the correct current value if the selector is in the 2 mA position?
0.25 mA
What is the correct current value if the selector is in the 0.5 DCmA position?
0.5 mA
The coulomb, whose alphabetical symbol is C, is defined as the total charge of ____?____ electrons.
6.25 × 10^18
What is the correct voltage if the selector is in the 200m DCV position?
1.5 mVDC
What is the correct current value if the selector is in the 20 mA position?
14.3 mA
What is the correct resistance when the meter switch is in the "200" position?
142.5 Ω
What is the correct voltage if the selector is in the 30 DCV position?
2 VDC
What is the correct current value if the selector is in the 25 DCmA position?
20 mA
What is the correct voltage if the selector is in the 1,000 DCV position?
277 VDC
What is the correct resistance when the meter switch is in the "X100" position?
50 kΩ
What is the correct resistance when the meter switch is in the "X1'' position?
50 Ω
What is the correct resistance when the meter switch is in the "X10" position?
50 Ω
What is the correct voltage if the selector is in the 600 DCV position?
500 VDC
What is the correct resistance when the meter switch is in the "2K" position?
500 Ω
What is the correct voltage if the selector is in the 150 DCV position?
60 VDC
What is the correct resistance when the meter switch is in the "20M" position?
All of the above (0.22 MOhms, 220 kOhms, 220,000 ohms)
When using an analog meter to measure DC current, how can the polarity of the current be determined?
By the direction of the meter needle's deflection.
Which formula will you likely use most often as an Electrical Worker?
Ohm's Law
The theory of current flow in which current flows from negative to positive is conventional current flow.
False
In order to measure current, the ammeter must be placed in parallel with the component for which the current is to be measured.
False (An ammeter must be placed in series with the component.)
Benjamin Franklin suggested that two types of charges existed, positive (+) and negative (-), and that "like" charges attract (positive to positive and negative to negative) and "unlike" charges repel (positive from negative).
False (Benjamin Franklin suggested that two types of charges existed, positive (+) and negative (-) and that "like" charges repel (positive from positive and negative) and "unlike" charges attract (positive to negative).
Ampacity is an invisible force that can produce heat, motion, light, and many other physical effects.
False (Electricity is an invisible force that can produce heat, motion, light, and many other physical effects.
Which diagram illustrates the correct method to measure the total voltage of the circuit?
Figure B
In Ohm's nomenclature, __ ?__ is the current in the circuit, __?__ is the voltage applied to the circuit, and __?__ is the total resistance of the circuit.
I / E / R
Is the ammeter connected correctly?
Is the ammeter connected correctly? No, the ammeter is connected backward, which could cause damage to the ammeter.
Any time one is measuring the resistance of a circuit, power should be removed from the circuit.
True
One ohm is defined as the amount of resistance in a circuit so that when one volt is applied to the circuit, one ampere of current will flow.
True
Does the diagram illustrate the correct method to measure the resistance across Resistor 1?
No, with the meter connected this way, it will read the resistance of Resistor 1 and Resistor 2.
The amount of current flowing through a circuit can be measured with a meter called an ammeter.
True
The purpose of voltage in an electrical circuit is to cause electrons to flow.
True
When measuring current in a circuit, what current scale should the meter be set on before performing the measurement?
The highest setting
The theory of current flow in which current flows from positive to negative is conventional current flow.
True
When the current level is continuously changing in a circuit, an analog meter should be used.
True
What is the correct procedure to adjust the indicator to read resistance measurements correctly when performing resistance measurements with an analog meter?
The test leads for the meter are "shorted together", and then the "0 Ω Adjustment'' control is adjusted to give a "0 Ω'' reading on the meter.
electron
This circuit illustrates __?___ flow.
A measure of the movement of electrons as 1 coulomb per second past a fixed point is a(n) ____?__ .
ampere
The unit of current flow is the ___?___ , which is represented by the alphabetical symbol I in Ohm's Law.
ampere
Other terms that are often used interchangeably with the term "potential difference" are voltage and _________________ .
electromotive force
The term electricity is derived from the Greek word ___?___ , and means "to be like amber."
elektron
Electricity is the movement of electrons that have been ____?__ by an external energy.
energized
The instrument used to measure resistance is a(n) __?___.
ohmmeter
Resistance is measured in ohms, which is represented in circuits by the Greek letter Ω which stands for ___?__
omega
What is the correct current value if the selector is in the 2 A position?
overload ( An overload or current value above the scale of the meter is indicated since no zeros are shown.( A reading of 1,000 would indicate 1 amp while a reading of 1. indicates an overload. The current should be measured using the 10A scale.)
As electrons flow through a conductor, the number of electrons is measured by __? __.
the number of coulombs per second that move past a fixed point in the circuit
An electrical potential of one __?___ will cause one coulomb of current to do one joule of work.
volt
A(n) ___?____ is used to measure the potential difference or difference in pressure in a circuit.
voltmeter
What is the correct voltage if the selector is in the 20 DCV position?
−17.26 VDC