Data Sheet

Project 6:
Compare the LED current (measured on the meter)
to the current with the lamp (you can also try it with
the meter on the 1mA setting instead of the 1A set-
ting). How do they compare?
The LED current is around 10 times less than the
lamp current.
Would you rather use incandescent light bulbs or
LEDs to light your home?
LED
Notice that white LED has a “+” polarity marking, but
the lamp does not. What do you think would happen
if you flipped the LED or lamp around in this circuit?
(Try it.)
The LED will not light but the lamp (L4) will.
Project 7:
You can swap the location of the lamp with the 3-
snap wire or slide switch in this circuit, then measure
the voltage across each of those parts and calculate
their resistance using Ohm’s law. What do you think
their resistance will be?
They should be less than a ohm.
Project 8:
Name at least 10 things in your home that use
switches.
Lights, Fan, Telephone, TV, Doorbell, AC, Oven,
Refrigerator, Hairdyer, Toaster.
Project 11:
Which gave a higher reading on the meter, long nar-
row shapes or short wide shapes?
The short wide shape.
Project 12:
Calculate the resistance of the motor, with and with-
out the fan. How does your calculation of the motor’s
resistance compare with its typical resistance? What
factors could have caused the difference?
Your calculations should be close to the typical re-
sistance. The fan causes the motor to spin slower.
Calculate the power of the motor, with and without the
fan. Does the motor use more power when the fan is on
it? Why?
The motor draws more current with the fan attached,
using more power. The slower the motor’s shaft is spin-
ning, the lower its electrical resistance.
Project 13:
Use Ohm’s Law to calculate the resistance of the
electromagnet’s resistance, and compare with its
typical resistance.
The resistance should be appropriately 30 ohms.
Project 14:
How would the current change if you replaced one
of the lamps with a 3-snap wire? (Try it.)
The current increases a little.
How would the current change if you replaced two of
the lamps with 3-snap wires? (Try it.)
The current increases more than before.
How would the current change if you replaced one
of the lamps with the white LED (D6)? (Try it, ori-
ented in both directions.)
When the LED lights the current is very low; no cur-
rent when the LED is off.
How will the circuit performance change if you re-
arranged the parts in the circuit? (Try it, but note that
the meter and battery holder only fit one way.)
There will be no change since it a series circuit.
Project 15:
How would the voltage change if you replaced one
of the lamps with a 3-snap wire? (Try it.)
The voltage would be higher.
How would the voltage change if you replaced one
of the lamps with the white LED (D6, “+” on the
right)? (Try it.)
The voltage would be higher.
Project 16:
How would the current change if you removed one
or two lamps? (Try it.)
The current decreases.
How would the current change if you replaced one
of the lamps with the white LED (D6)? (Try it.)
The current decreases. The LED uses very little cur-
rent.
Project 17:
How would the voltage change if you replaced your
batteries with ones that are weaker or stronger? (Try
it if you have different batteries available.)
Weaker Battery- The voltage will be lower.
Stronger Battery - The voltage will be higher.
How would the voltage change if you left the switch
(and lamps) on for a long time?
The voltage will decrease.
How would the voltage change if you removed one
or two lamps? (Try it.)
The voltage will not change, or may rise slightly.
How would the voltage change if you replaced one
of the lamps with the white LED (D6)? (Try it.)
The voltage will not change, or may rise slightly.
Project 18:
Give some examples of parallel circuits in your
home.
Wall outlets
Room Lights
Project 19:
Give some examples of series circuits in your home.
A wall switch and lamp.
SC-STEM1 Answers to Project Questions