MARWADI EDUCATION FOUNDATIONS GROUP OF INSTITUTIONS

(MEFGI) Department of Electronics and Communication Engineering

Electronic Measurements & Instrumentation Lab (151005)

Experiment 8 Experiment 8-a Objective:

Study of DC and AC Voltage Measurement. Apparatus Required:

1. DC Supply (whose voltage you want to measure) 2. AC Supply (whose voltage you want to measure) 3. Multimeter Test Probes 4. Patch Cords

Principle of DC Voltage Measurement: The first stage of Voltage Measurement is based on Voltage Divider Rule as shown in the

diagram below.

Function of Switches: 1. Toggle Switch is used to select the function either AC Volts or DC Volts. 2. Rotary Switch of Voltage Measurement Section is used to select the desired range of voltage. 3. Rotary Switch of Display Section is used to select decimal place.

Procedure: DC Voltage Measurement:

1. First of all connect the mains cord to the trainer NV7106 & make sure that the Power Switch of trainer is at Off position. 2. Set the both toggle switches of Voltage Measurement Section at DC position. 3. Set the rotary switch of Voltage Measurement Section at desired range which you want to measure. (For Example to measure 15V keep rotary at 20V position) 4. Set the rotary switch of Display Section to select the decimal place.

Note: Position of both rotary (Voltage Measurement Section & Display Section) must be same. For example to measure 15V keep both rotary at 20 position.

5. Connect the Output of Voltage Measurment Section to Display Section using patch cords with rigth polarity. 6. Now switch on the trainer.

7. DC Voltage which you want to measure, connect to Input of Voltage Measurement Section with the help of given red & black test probe with right polarity.(Red Socket = positive & Black Socket = negative or common).

Note : In case of voltage measurement, multimeter is always connected in parallel of the circuit. 8. Now you can see the DC voltage you want to measure on the Display.

Note: In case of measuring unknown DC voltage then display showing Over Range (i.e. 1 is shown on the display) then set rotary switch of Voltage Measurement Section at

higher position. Principle of AC Voltage Measurement :

The principle of voltage measurement of Voltage Divider Rule is also followed in case of AC Voltage Measurement. The only difference between AC and DC Voltage Measurement is that of capacitor.

In case of AC Voltage Measurement, a capacitor is used between the input voltage and voltage divider circuit. Capacitor is used to filter out the DC component in the AC input voltage.

In case of AC Measurement, dropped AC should be converted into DC for ADC to work and for displaying the voltage on 7 segment display. Procedure: AC Voltage Measurement:

1. First of all connect the mains cord to the trainer NV7106 & make sure that the

Power Switch of trainer is at Off position. 2. Set the both toggle switches of Voltage Measurement Section at AC position. 3. Set the rotary switch of Voltage Measurement Section at desired range which you want to measure. (For Example to measure 15V keep rotary at 20V position) 4. Set the rotary switch of Display Section to select the decimal place.

Note: Position of both rotary (Voltage Measurement Section & Display Section) must be same. For example to measure 15V keep both rotary at 20 position. 5. Connect the Output of Voltage Measurment Section to Display Section using patch

cords with rigth polarity. 6. Now switch on the trainer. 7. AC Voltage which you want to measure, connect to Input of Voltage Measurement

Section with the help of given red & black test probe with right polarity.(Red Socket = positive & Black Socket = negative or common).

Note: In case of voltage measurement, multimeter is always connected in parallel of the circuit.

8. Now you can see the AC voltage you want to measure on the Display. Note: In case of measuring unknown AC voltage then display showing Over Range (i.e.

1 is shown on the display) then set rotary switch of Voltage Measurement Section at higher position. Note : As this is a traning equipment, the lengnth of tracks & wires increases resulting in rise

of the internal resistance.This resistance contribute in the measurement so the values of measurement deviates from the values of actual multimeter.Also this affects the accuracy in various ranges. Actual Multimeter are compact in design so it is accurate than our trainer.

Experiment 8-b Objective:

Study of DC and AC Current Measurement. Apparatus Required:

1. DC Supply 2. AC Supply 3. Multimeter Test Probes 4. Patch Cords

Principle of Current Measurement:

The first stage of Current Measurement is based on Current to Voltage Conversion through a shunt as shown in the diagram below.

In case of current measurement, the input current flows through the resistance which is

selected for the Current Range using Rotary Switch S4. So current can be calculated in terms of voltage (across the resistance of Current Range) by the formula V = IR. In each case of current range, the maximum voltage across the resistance is 2 Volt calculated by the formula V = IR.

Procedure: DC Current Measurement :

1. First of all connect the mains cord to the trainer NV7106 & make sure that the Power Switch of trainer is at Off position.

2. Set the toggle switch of Current Measurement Section at DC position. 3. Set the Rotary of Current Measurement Section at desired range which you want to measure. (For Example to measure 3mA keep rotary at 20mA position) 4. Set the rotary switch of Display Section to select the decimal place.

Note: Set following positions of rotary switch of Display Section according to the selected range of Current Measurement Section

5. Conncet Output of Current Measurement Section to Display Section using patch cords with right polarity.

6. Now switch on the trainer. 7. Circuit (or Supply) by which you want to measure the current in series connect to Input

of Current Measurement Section with the help of given red & black test probe with right polarity.(Red Socket = positive & Black Socket = negative or common & Yellow Socket = For 2 Ampere range)

Note: To measure the current flow, multimeter and circuit are connected in series. 8. Now you can see the DC Current you want to measure on the Display.

Note: In case of measuring unknown DC Current then display showing Over Range (i.e. 1 is shown on the display) then set rotary switch of Current Measurement Section at higher position.

Position of rotary switch of Current measurement Section

Position of rotary switch of Display Section

200A 200

2mA 2

20mA 20

200mA 200

2A 2 AC Current Measurement:

1. First of all connect the mains cord to the trainer NV7106 & make sure that the Power Switch of trainer is at Off position.

2. Set the toggle switch of Current Measurement Section at AC position. 3. Set the Rotary of Current Measurement Section at desired range which you want to measure. (For Example to measure 3mA keep rotary at 20mA position) 4. Set the rotary switch of Display Section to select the decimal place.

Note: Set following positions of rotary switch of Display Section according to the selected range of Current Measurement Section

Position of rotary switch of Current measurement Section

Position of rotary switch of Display Section

200A 200

2mA 2

20mA 20

200mA 200

2A 2

5. Conncet Output of Current Measurement Section to Display Section using patch cords with right polarity.

6. Now switch on the trainer. 7. Circuit (or Supply) by which you want to measure the current in series connect to Input

of Current Measurement Section with the help of given red & black test probe with right polarity.(Red Socket = positive & Black Socket = negative or common & Yellow

Socket = For 2 Ampere range) Note: To measure the current flow, multimeter and circuit areconnected in series.

8. Now you can see the AC Current you want to measure on the Display. Note: In case of measuring unknown AC Current then display showing Over Range (i.e. 1 is

shown on the display) then set rotary switch of Current Measurement Section at higher position. Note: As this is a traning equipment, the lengnth of tracks & wires increases resulting in rise of the internal resistance.This resistance contribute in the measurement so the values of measurement deviates from the values of actual multimeter.Also this affects the

accuracy in various ranges. Actual Multimeter are compact in design so it is accurate than our trainer.