LAB #1
“BASIC OF DIGITAL MULTIMITER”
A) Measurements of DC and AC Voltage:
1. Connect the power supply to the DMM (DIGITAL MULTIMETER).
2. Set a voltage equal to VDC = 11.95 V on the power supply and select the VDC mode and the
manual RANGE on the DMM. Choose the best range to obtain measurements more accurate as
possible.
3. Set a voltage equal to VDC = 12.05 V on the power supply and select the VDC mode and the
manual RANGE on the DMM. Choose the best range to obtain measurements more accurate as
possible.
Note: RANGE (Full Scale) has been changed and the DMM ACCURACY too.
4. For all measurements calculate the Accuracy and the uncertainty;
5. Repeat ten times point 2 and evaluate measurement/power supply repeatability.
B) Measurements of AC Voltage and use of function generator:
1. Connect the Function Generator (FG) to the DMM.
2. Adjust the proper output impedance for the DMM input. (D:SYS_Menu OutTerm HIGH Z)
3. Set on the FG an sinusoidal AC Voltage [VAC = V0sin(2f0*t)]., VO = 10Vpp and f0 = 100 Hz.
Measure VO and sketch the point on a Bode diagram.
4. Set on the FG an sinusoidal AC Voltage [VAC = V0sin(2f0*t)]., VO = 10Vpp and f0 = 1 kHz.
Measure VO and sketch the point on a Bode diagram.
5. Set on the FG an sinusoidal AC Voltage [VAC = V0sin(2f0*t)]., VO = 10Vpp and f0 = 10 kHz.
Measure VO and sketch the point on a Bode diagram.
6. Set on the FG an sinusoidal AC Voltage [VAC = V0sin(2f0*t)]., VO = 10Vpp and f0 = 100 kHz.
Measure VO and sketch the point on a Bode diagram.
7. Set on the FG an sinusoidal AC Voltage [VAC = V0sin(2f0*t)]., VO = 10Vpp and f0 = 1 MHz.
Measure VO and sketch the point on a Bode diagram.
8. Set on the FG an sinusoidal AC Voltage [VAC = V0sin(2f0*t)]. VO = 10Vpp e f=10 MHz.
9. Highlight the bandwidth of the DMM.
C) Measurements of AC/DC Voltage and use of function generator:
1. Set on the FG an sinusoidal AC Voltage VAC = VOsin(2fot)+VDC. VO = 10Vpp ; f = 1 kHz and
VDC = 2V. Measure the RMS AC coupled, the VDC and RMS DC coupled.
2. For all measurements calculate the Accuracy and the uncertainty;
D) Measurements of AC Current and use of Power Supply:
1. Following the schematic reported in the following figure, realize the circuit and measure I1 and
I2 currents flowing in the R1 and R2 resistor respectively.
2. Measure the total current I3.
3. For all measurements calculate the Accuracy and the uncertainty;
I 
V0
R eq
where:
R eq 
R1  R2
R1  R2
R1
R1  0.1 , 7 W
R 2  100 , 0.25 W
I1
A1
I
A
R2
I2
A2
V0=200 mV
E) Measurements of AC Current and use of Function Generator:
1.
2.
3.
4.
5.
6.
Following the schematic reported in the previous figure, realize the circuit.
Replace the power supply by a function generator;
Set on the FG an sinusoidal AC Voltage [VAC = V0sin(2f0*t)]., VO = 10Vpp and f0 = 10 kHz..
Measure I1 and I2 currents flowing in the R1 and R2 resistor respectively.
Measure the total current I3.
For all measurements calculate the Accuracy and the uncertainty;