Data Sheet

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47. Electrical Current Detector
Build the circuit as shown on the left. You will light up the
heart LED (69) at once. If you want to turn on the star LED
(70), you should turn on the switch (62) or the press switch
(61). The star LED (70) in this circuit is a very simple device
that can be used to detect current ow. A more advanced
device, called an ammeter, is used to measure the amount of
electrical current owing in a circuit.
48. House Alarm
Build the circuit as shown on the left. Turn on the switch (62)
or touch the reed switch (83) with magnet (7) and you will
light up the lamp (76) and you will hear the alarming sounds
from the alarm (78).
This simulates a house alarm system where the reed switch
(83) acts like a motion sensor and sets off an alarm when the
magnet (7) is moved near it (simulating motion in the house).
The switch (62) acts like a test button where you can test
that the alarm system is working by pressing the switch (62).
2nd level
1st level
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