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Alarm system
YOU WILL NEED
+ 2 resistors, 470 Ω
+ 1 resistor, 3.3 kΩ
+ 1 resistor, 22 kΩ
+ 1 resistor, 100 kΩ
+ 1 resistor, 220 kΩ
+ 1 capacitor 10 µF
+ 2 LEDs
+ 2 transistor modules
+ 1 pushbutton
+ 6 short wire bridges
+ 1 long wire connector
+ electronics board
+ battery clip
+ and additional household
item: 9-volt square battery
HERE'S HOW
1. Assemble your alarm system.
2. Connect the contact clips marked
"A" and "B" with a long wire.
3. When you hook up the battery and
push briefly on the pushbutton, the
red LED (LED2) goes out.
4. The alarm system is now
ready for you to test it by
pulling the long wire out of
the circuit.
A
C1
10 µF
R6
220 kΩ
LED2
A
A
LED1
C
R2
R4
470 Ω
Pb1
22 kΩ
R3
T1
100 kΩ
B
R 6
R 1
470
220 k
LED 1
C 1
10 F
Ta 1
Alarm Systems
EXPERIMENT 5
R1
+
470 Ω
C
–
R5
3.3 kΩ
T2
LED 2
R 5
3.3 k
R 2
470
R 3
T2
100 k
T1
R 4
22 k
23
+
9V
–
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