Datasheet-2

Project 33:
Study the circuit. What will happen to the motor,
lamp, and meter if you change the switcher to the
bottom position? (Try it.)
The motor spins in the other direction but and the
lamp and meter do not change.
Project 34:
When S1 and S6 are off the top lamp should be dim
or off, why?
The lamp will be off because the motor has high re-
sistance without the fan, limiting the current.
The motor could not start spinning with the other
lamps on, but it will keep spinning as long as you
keep pushing S2. Why?
Once the initial friction is overcome, it doesn’t take
much effort to keep the motor spinning.
Project 35:
Compare the voltage measurements with out the fan
to those with the fan.
The voltage will be lower with the fan.
Project 36:
Turn on the slide switch and set the switcher to the
right (so both switches are on), and push the press
switch to get the fan spinning fast. Now turn off the
slide switch and watch how long it takes to light the
middle lamp; how long does it take to light, and why?
It takes a few seconds because the current is lower.
Project 38:
Why does the fan affect the lamp brightness?
The motor has low resistance when the shaft isn’t
spinning fast, allowing a higher current to make the
lamps bright.
Project 39:
Remove the fan from the motor and compare the
current. Why is it higher or lower?
It takes more current to spin the motor’s shaft with
the fan on.
Project 40:
Using this and the preceding circuit, compare the
current and voltage for each switch. Does the voltage
drop more when the current is higher?
Yes, the battery voltage drops slightly due to the high
current it is pushing.
Project 41:
How do you think the measured voltage in the top
circuit would be affected if you added 100 more
lamps to the circuit?
Adding more lamps overloads the battery so the volt-
age drops a little.
Project 46:
Name some items that use magnets:
Audio speaker, electric fan, alarm system, refrigerator
door, washer and dryers,
Project 47:
Names some advantages and disadvantages of
electronic magnets compared to permanent mag-
nets.
The strength of an electromagnet can be adjusted,
while a permanent magnet is fixed. A permanent
magnet does not require a electric current. A per-
manent magnet losses its magnetic properties
when over heated.
Project 52:
How could you make this electromagnet more pow-
erful?
Adding more loops of wire to a coil.
Project 53:
How does the build-your-own electromagnet used
here compare with the wire magnet used in the pre-
ceding project? Which is more powerful?
The build-your-own electromagnet is more powerful be-
cause it has more loops of wire.
How does it compare to the M3 electromagnet used
in project 49?
The build-your-own electromagnet is less powerful be-
cause it has fewer loops of wire.
Project 59:
Compare the electrical energy produced by the gen-
erator (the motor): Is the voltage higher with or with-
out the fan?
The voltage is lower with the fan on.
Is the current higher with or without the fan?
The current is higher with the fan on.
Does the voltage/current last longer with or without
the fan?
The voltage/current lasts longer with the fan on.
Project 60:
If you replace the white LED with the lamp (L4), how
bright will the lamp get? (Try it, both with and without
the fan.)
The lamp will not light.
Project 64:
How bright will the white LED flash if you remove the
2-snap wire from the circuit (to disconnect the elec-
tromagnet? (Try it.)
The LED will not light with the two snap removed.
Project 65:
Replace the relay (S3) with the lamp (L4). Does the
white LED flash?
No, because the lamp does not have a coil or magnetic
field.
Project 66:
What could you use a reed switch for?
Alarms- Window and door sensors
Project 69:
List some devices in your home that use relays.
Refrigerator, Oven, Thermostat
What is the main reason to use a relay?
Allow low voltage devices to control high voltage de-
vices.