Experiment # 1

Introduction Instrumentation and Measurements Trainer

Objectives: List the basic components of Instrumentation and Measurements Trainer

and their function.

Apparatus required: DIGIAC 1750 Transducer and Instrumentation Trainer

List of basic components:

• Amplifier • Swimming Amplifier
• Buffer • Differential Amplifier
• 100X Gain Amplifier • Instrumentation Amplifier
• Comparator • Ac Amplifier
• Power Amplifier • Low pass Amplifier
• Current Amplifier • Integrator
• Differentiator • Wire wound track
• Inverter • Counter/timer
• 40kHz oscillator • Relay
• Alarm oscillator • Electronic switch
• V/F converter • Solenoid
• F/V converter • Buzzer
• V/I converter • Humidity Sensor
• I/V converter • Ultrasonic receiver
• Full wave rectifier • Ultrasonic transmitter
• Sample & hold • Microphone
• Strain gauge • Loudspeaker
• Air processor sensor • DC Moter
• Air flow sensor • Slotted OPTO sensor
• Air valve • Reflective OPTO sensor
• Variable resistor • Inductive sensor
• Wheatstone bridge • Hall effect sensor
• Carbon track • Techogeneator
 Experiment # 2
Positional Resistance Transducers
Objectives:

• Plot the Variation of Output voltage with the control Setting of Rotary
Potentiometer
• Plot the Variation of Output voltage with the control Setting of the Slide
Potentiometer
2.1-Practical Exercise: Plot the Output voltage Variation with the control Setting of
the Rotary Potentiometer.

• Connect the circuit as shown in Fig using a DC power supply

and a digital multimeter.
• Adjust the 100kΩ rotary resistor control to the fully counter-
clockwise position, aligning it with setting 1 as illustrated in the
figure. Please note that the dial does not feature numerical
markings on the printed panel.
• The voltage adjustment has been accurately configured,
proceed to activate the power supply. Observe the output
voltage displayed on the digital multimeter and document this
information in the table.

Control 1 2 3 4 5 6 7 8 9 10
Sitting
Output 0.48 0.75 2.24 3.88 5.73 6.43 8.07 9.51 11.03 11.93
Voltage

Adjust the rotary control to “2” and repeat the reading, recording in Table
• Repeat the reading and recording for all other settings of the rotary
control.
• From the results recorded in the Table above plot the characteristic of
the 100kΩ variable resistor on the graticule of the Graph.

Voltage across this section (V9 –V2) =10.28V

Voltage per division (V9 –V2 /V9-2) =1.49V

Enter your Voltage per Division =1.49 V/di

 Y-Values
14
11.93
12 11.03

9.51
10
Output Voltage

8.07
8
6.43
5.73
6
3.88
4
2.24
2 0.75
0.48
0
0
0 2 4 6 8 10 12
Control Sitting

2.2- Practical Exercise: Plot the Variation of Output voltage with the control Setting
of the Slide Potentiometer

• Connect the circuit as shown in Fig using a DC power supply

and a digital multimeter.
• Adjust the 10 kΩ slide resistor control to the left, positioning it at
setting 1 as illustrated in the figure. It is important to note that
the indicated numbers are not present on the printed panel turn
ON the power supply.
• Observe the output voltage displayed on the digital multimeter
and document it in the table.

Control
1 2 3 4 5 6 7 8 9 10
Setting
Output
-5.04 -4.2 -3.1 -1.8 -0.7 0.4 1.6 2.8 3.9 5.0
Voltage
 • Adjust the control to "2" and repeat the reading.
• Repeat the readings for all other settings of the slide control, recording
the result in Table.
• From the results recorded in Table plot the characteristic of the 10kΩ
slide resistor with dual polarity supply on the graticule of Graph
• Turn OFF the power supply and remove the connections between the
slide potentiometer and the power supply panels
• By using the digital multimeter adjust the range (20kΩ) to measure the
resistance between terminal A and wiper B with the wiper set to position
9:
• Move the wiper to position 2 and repeat the resistance measurement:

Resistance R9 =10.5 kΩ

Resistance R2 = 1.8 kΩ

Resistance between settings R9 & 2 = R9 - R2 = 8.7 kΩ

Voltage between settings 9 & 2 = V9 - V2= 8.1 V

Voltage Per kΩ = V9 – V2 / (R9 – R2) kΩ= 0.93V/kΩ

Enter your Voltage per kΩ = 0.93V/kΩ

4
2.8
3

2 1.6

1 0.4
0
Output Voltage

0
-0.7
-6 -5 -4 -3 -2 -1 0 1 2 3 4
-1
-1.8
-2
-3.1
-3
-4.2
-4
-5
-5

-6
Control Sitting
 Experiment # 3
Wheatstone bridge Measurements
Objectives:
• Set the offset control of the null detector
• Measure the unknown resistance by using the Wheatstone bridge
• Measure the unknown variable resistance by using the Wheatstone
bridge
Apparatus required:
• DIGIAC 1750 Transducer and Instrumentation Trainer.
• 4mm Connecting Leads. Digital Multimeter.

Procedure:
3.1 - Practical Exercise:Set the offset control of the null detector

The initial setup of the amplifier and meter configuration, which constitutes the
sensitive galvanometer, must ensure that a zero input results in a zero output
when the gain is adjusted to its maximum level.
 Connect the circuit as shown in Fig with the + & - inputs of the
Differential Amplifier are short-circuited, resulting in a zero input.
Adjust the GAIN COARSE control of Amplifier #2 to 10 and set
the GAIN FINE to 1.0.
 Turn ON the power supply and modify the OFFSET control until
the moving coil meter displays an approximate zero reading.
Subsequently, adjust the GAIN COARSE control to 100 and
fine-tune the OFFSET control to achieve an exact zero output.
 This adjustment is notably sensitive. Therefore, you were
advised to initially establish an approximate setting with the gain
configured to 10.
Measure the unknown resistance by using the Wheatstone Bridge.

• The switch on the Wheatstone bridge circuit is positioned in the IN

setting. Adjust the GAIN COARSE control of Amplifier #2 to a value of
10, and proceed to connect the circuit as in the figure.
• Adjust the control of the 10-turn variable resistor so that the moving coil meter
reading is approximately zero, then set the GAIN COARSE control to 100.
Finally, adjust the 10-turn resistor control accurately for zero meter (null)
reading to balance the bridge.

To interpret the dial: If the coarse setting displays the number 3 and the fine setting
shows 74, the overall dial reading is 374.
• Please record the resistor dial reading on the reverse side.

Dial reading = 200

Resistance R3 = 10 x dial reading = 2kΩ

Resistance R1 = 10,000 - R3= 8 kΩ

Resistance R2 = 12,000Ω = 12 kΩ

Unknown resistance Rx = x R3 = 3 kΩ

Measure the unknown variable resistance by using the Wheatstone bridge

Conduct additional resistance measurements on the 10kΩ slide variable resistor to enhance
your understanding of the equipment and its adjustments as outlined below:

• Adjust the Wheatstone bridge switch to OUT to remove the unknown

resistor Rx from the circuit. Connect the l0kΩ Slide variable resistor
terminals A & B to the Wheatstone bridge circuit connections C & 0V.
• With the l0kΩ resistor control adjusted to maximum, measure its
resistance as follows.
• Test that the amplifier offset is adjusted correctly and adjust if
necessary.
• Amplifier #2 GAIN COARSE control adjusts to 10, obtain an
 approximate balance by adjusting the 10-turn resistor.
• Adjust Amplifier #2 GAIN COARSE control to 100 and obtain final
balance. Note the dial reading and enter the value in the Table.
• Repeat the procedure to measure the resistance of the l0kΩ resistor
for all settings from
• Calculate the resistance corresponding with each reading, recording
the results in Table R2 is still l2kΩ.

10KΩ Dial Reading at

Resistor R3 (10 × Dial) R1 (10 KΩ- R3) R4 = × R3
Setting Balance
10 29 2.9 kΩ 7 kΩ 5.2 kΩ
9 270 2.7 kΩ 7.3 kΩ 4.9 kΩ
8 235 2.4 kΩ 7.6 kΩ 4.7 kΩ
7 214 2.1 kΩ 7.9 kΩ 4.5 kΩ
6 169 1.7 kΩ 8.3 kΩ 4.3kΩ
5 128 1.3 kΩ 8.7 kΩ 4.1kΩ
4 74 0.74 kΩ 9.2 kΩ 3.9 kΩ
3 16 0.16 kΩ 9.8 kΩ 3.8 kΩ
2 5 0.05 kΩ 9.9 kΩ 3.6 kΩ
1 2 0.02kΩ 10 kΩ 3.5 kΩ