Vocabulary
Name the Symbol
Calculating Total Resistance
Resistors
Theory
100
What is a conductor? Give an example.
Conductors are components that electrical current from the power source to the load devices.
An example is copper wire.
100
Name this symbol:
Battery
100
What is the formula for total resistance in a series circuit?
Rt = R1 + R2 + R3+....+Rn
100
What is the purpose of a resistor?
A resistor limits the flow of electrical current through a circuit.
100
What are the units and symbols for Voltage, Resistance, and Current?
Voltage - Volts - V
Resistance - Ohms - Ω
Current - Amphers - A
200
How do fuses work?
Fuses contain a calibrated copper wire that only allows certain electric current through. When the electric current is too high, the copper wire breaks so that the current cannot pass which protects the component.
200
Name this symbol:
Fuse
200
What is the formula for total resistance in a parallel circuit?
1/RT = 1/R1 +1/R2 + 1/R3+....+1/Rn
200
What is the value of a resistor with the following colors: Black, Brown, Yellow, Silver
10KΩ ±10%
200
What is the difference between these two circuits?
The second circuit will produce a short circuit. The current will flow through the path of least resistance.
300
What is a load or a load device? Give examples.
A load device is a component that receives electrical energy from the power source and converts it in to other types of useful energy. Examples include resistors, lamps, motors, and buzzers.
300
Name this symbol:
Double two-way switch
300
Calculate the total resistance of a series circuit with the following resistance: R1=8Ω, R2=10Ω, R3=30Ω, and R4=12Ω
Rt =8Ω+10Ω+30Ω+12Ω
Rt =60Ω
300
What is the value of this resistor?
10KΩ ±5%
300
Which orientation is the best for connecting the buzzer in a circuit where the resistor is located?
You must connect the positive pole of the buzzer to the same wire that is connected to the positive pole of the battery.
400
What is another word used to express voltage?
Potential Difference
400
Name this symbol and explain its function.
LED (Light-emitting diode). It conducts electricity only when the current flows from the positive (anode) to the negative (cathode) terminals of the LED.400
Calculate the total resistance in a parallel circuit with the following resistance: R1=2Ω, R2=3Ω, R3=6Ω, and R4=18Ω
1/Rt = 1/2Ω +1/3Ω+1/6Ω+1/18Ω
1/Rt = 9/18Ω + 6/18Ω +3/18Ω +1/18Ω
1/Rt =19/18Ω
Rt =18/19Ω
Rt = 0.947Ω
400
What is the value of the following resistor?
22MΩ ±5%
400
There are two circuits each with 3 bulbs. One is connected in parallel and one in series. Which bulbs will shine brighter? What is the antonym of brighter?
Series Parallel
The bulbs in parallel are brighter and the bulbs in series are dimmer.
In a series circuit the voltage is divided by the number of bulbs:
Vt =V1 + V2 + V3
In parallel the voltage across all bulbs are the same: Vt =V1 = V2 = V3
500
Which two directions do motors rotate?
Clockwise or Anti-clockwise (Counterclockwise in American English)
500
Name this symbol and explain what happens if we place a light bulb in series with it.
Potentiometer. If we regulate the potentiometer to the maximum resistance, the current will be reduced and therefore the light bulb will be dimmer. We use it to control the brightness of the light bulb.
500
Find the total resistance of the following circuit:
Find total resistance of parallel resistors:
1/Rtp = 1/R2 + 1/R3
1/Rtp = 1/30Ω+ 1/50Ω
1/Rtp = 5/150Ω + 3/150Ω
1/Rtp = 8/150Ω
Rtp = 150/8Ω = 18.75Ω
Now find total resistance.
Rt = R1 + Rpt + R4
Rt = 20Ω + 18.75Ω +20Ω
Rt = 58.75Ω
500
What is the value of a resistor with the following colors: Violet, Green, Silver, Silver
0.75Ω ± 10%
500
Which component do you have to place in serial with a LED to avoid damage? What is its value?
A resistor because it reduces the amount of current that flows through the LED. The value is 220Ω