ThӵFKành cҧPELӃQ
1
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ThӵFKành cҧPELӃQ
2
1. MөFÿtFK
*L~SVLQKYLrQFiFKÿRÿҥFWKXWKұSYà hiӇQWKӏJLá trӏFӫDPӝWVӕORҥLFҧPELӃQ
thông dөQJ
2. Yêu cҫX
7KDPJLDÿҫ\ÿӫFiFEXәLKӑFOêWKX\ӃWYà thӵFKành.
3. NӝLGXQJP{QKӑF
SӱGөQJEӝWKtQJKLӋP./-ÿӇÿRÿҥFYà lұSWUình hiӇQWKӏ
-CҧPELӃQWLӋPFұQ3UR[LPLW\
-CҧPELӃQQKLӋWÿӝ7HPS37-100)
-CҧPEiӃQJyFTXD\5RWDWLRQ$QJOH
-CҧPELӃQUXQJVibration)
-CҧPELӃQhӗQJQJRҥL (Infrared)
-CҧPELӃQTXDQJ&'6
ThӵFKành cҧPELӃQ
3
1.1. CҧPELӃQWLӋPFұQ
Inductive proximity sensors are widely used in various applications to detect
metal devices. They consist of an oscillator, trigger, and switching amplifier. If a

CC
Output
GND
Oscillator
Trigger
Switching
Amplifier
S
S
y
y
m
m
b
b
o
o
l
l
:
:
(
(
E
E
q
q
u
u
i

Vo = LOW Æ Vo22 = High Æ Q1 ON Æ Buzzer ON
Experiment Procedure:
1. Insert proximity sensor to 3 pin module socket.
2. Power on the module
3. Use different type of object to approach to the detecting head and observe the
result. Æ
ThӵFKành cҧPELӃQ
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1.2. CҧPELӃQQKLӋWÿӝ
PT-100 is one form of the RTD (Resistance Temperature Detector). It is made of
the platinum wire and has the resistance of 100 ohm at 00C. The resistance vs.
temperature characteristic of PT-100 can be expressed as:
RT = 100 (1+0.00392T)
If constant current I of 2.55mA flow through PT-100
VB’ = I x RT = (255+T)mV
Circuit Explanation:
Temperature (PT100) Sensor
Stainless-steel protection tube
(Platinum wired wound inside)
A
B
B’
B=B’
S
S
y
y
m
m
b

ThӵFKành cҧPELӃQ
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• VR2 is used to control the constant current source to 2.25mV
• U1 is non-inverting amplifier
Æ V16= (2550+10T) mV
• U2 is differential amplifier
• U3 is voltage follower
Æ Adjust VR14 to control Vf1 (offset of U2)
• So if Vf1 = 2550mV Æ Vo27 = 100T mV Æ Conversion Ratio = 100mV / 0C
Experiment Procedure:
In this exercise, you need to prepare a thermometer (mercury) for calibration.
1. Using thermometer to record the current room temperature (T).
Æ
?
2. Connect 2 lead wires (white) to B and B’, and lead wire (red) to A.
3. Power on the module.
4. Adjust VR2 until VB’ = (255+T)mV
Æ
?
5. Adjust VR14 until Vo27 is equal to T/10 V (Calibration complete)
Æ
?
6. Put both PT-100 and the mercury thermometer inside hot water.
7. What is the value shown on the mercury thermometer?
Æ
?
8. What is the output voltage of Vo27?
Æ
?
9. Put both PT-100 and the mercury thermometer inside cold water.

c
c
t
t
u
u
r
r
e
e
:
:
Knob
Plastic Housing
CW
CCW
Output
(sliding connection)
Excitation
Voltage
Vout
S
S
y
y
m
m
b
b
o

ThӵFKành cҧPELӃQ
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1.4. CҧPELӃQUXQJ
The vibration switch is normally open with vibration springs. When a vibration
occurred, the switch changes to close state and the switch turns ON.
Circuit Explanation:
Vibration Switch
Contact:
to spring
Contact
to metal
Housing
S
S
y
y
m
m
b
b
o
o
l
l
:
:
S
S
t
t

Infrared emits infrared radiation which is focused by a plastic lens into a narrow
beam. The emitting beam of an IR LED is generally proportional to the magnitude of
the forward current (forward biased). The beam is modulated i.e. switched on and off,
to encode the data. The receiver uses a silicon photodiode to convert the infrared
radiation to an electric current for further processing.
Circuit Explanation:
Transmitter
(Infrared Emitting Diode)
Receiver
(Photodiode)
Anode
Cathode
Transmitter
Receiver
Vout_U2
Vout_U3
Infrared Sensor
ThӵFKành cҧPELӃQ
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U2: Inverting amplifier, Gain = ~1000
U3: differential amplifier, Gain = ~ 22
U4: Comparator, If V+ > V- Æ output = 12V || If V->V+ Æ output = -12V
Use VR2 to adjusted the output frequency f of the 555 Timer Æ Q1
switches ON and OFF Æ Infrared TX emits ON and OFF Æ If no object blocks
between TX and RX Æ Infrared RX receives ON and OFF Æ weak pulse signal
input to U2 Æ strong pulse signal Æ Vpp = 12V, frequency = f) output at
Vout_U2 Æ At resonant frequency Æ VLc obtain maximum Vpp Æ signal
amplify again though U3 Æ CR1, C5, R13 converts the AC signal into DC
signal at U4 pin3 Æ If U4 pin3 > U4 pin2 Æ Vo17 outputs high potential
Experiment Procedure:

u
c
c
t
t
u
u
r
r
e
e
:
:
S
S
y
y
m
m
b
b
o
o
l
l
:
:
ThӵFKành cҧPELӃQ
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When light strikes the CDS:

t
t
o
o
b
b
e
e
d
d
e
e
m
m
o
o
n
n
s
s
t
t
r
r
a
a
t
t
e
e