EGR 101 Exam #1
Units and Notation
Primary Units
Secondary Units
Scientific Notation
Engineering Notation
Principles of Electricity
Conductors, Insulators, and Semiconductors
Charge
Coulomb
Charge/Time = Current
DC Current --- Constant, do not change with time
Voltage – Joule/Coulomb
Resistance and Conductance
Resistivity
Determine resistance of a piece of material
Resistors
Standard Values
Tolerance
Color Coding
Potentiometers
Variable Resistor
Settings – Define the method
Ohm’s Law and Power
Relationship between current and voltage
V=IR
I=V/R
R=V/I
P=V2/R
P=I2R
Power
P=VI
Series Circuits
Elements in SERIES have the same current
Resistors is Series add together Req=R1+R2+…Rn
Voltages around a closed loop add together to equal the source voltage,
Sum of all of the voltage drops equals the sum of all the voltage rises
Kirhhoff’s Voltage Law (KVL)
Conservation of energy
Powers add together
Voltage Divider – find the voltage across one specific resistor
Vn=VS(Rn)/(Req)
Ground – Zero Volts – Reference Point
Measurement of Voltage, Current, and Resistance
DMM on Voltmeter Scales, Ammeter, DMM on Resistance Scales
Connected the leads in PARALLEL with the element to measure voltage
Connected leads in SERIES with the element to measure current (Break the
circuit to insert the ammeter)
Measure resistance across the element with one lead disconnected from
the rest of the circuit.
Series—Opposing and Series—Adding Sources