MODEL 120 TRUE RMS MULTIMETER
5.4 Resistance Measurements
WARNING
Before making any
1. | Connect the red test lead to the ‘:’ jack and the black test |
| lead to the ‘COM’ jack. |
2. | Set the Function Selector switch to the :function. |
3. | Ensure there is no power applied to the circuit, and then |
| connect the test leads in parallel with the circuit being |
| tested and read the measured resistance on the instrument |
| display. |
Manual range indication
Relative indication
Auto range indication
Data hold indication 
Low battery indication 
AC source 
DC source
Negative polarity indication 
Auto power off indication
Digital value indication
MODEL 120 TRUE RMS MULTIMETER
Maximum indication
Revolutions per minute
Minimum indication
Peak max/min indication
Diode indication
Continuity with beeper
Temperature indication
Capacitance indication
Voltage/current indication
Frequency indication
Resistance indication
Analog bar indication
5.5 Continuity Measurements |
WARNING
Before making any
1.Connect the red test lead to the ‘:’ jack and the black test lead to the ‘COM’ jack.
2.Set the Function Selector switch to the :
function.
3.Press the blue Second Function button once to select the 
function.
4.Ensure there is no power applied to the circuit, and then connect the test leads in parallel with the circuit being tested.
5.When the impedance between the test leads is less than 40:a continuous beeper will activate.
Open Circuit | Short Circuit |
5.6 Diode Tests
WARNING
Before making any
1.Connect the red test lead to the ‘ 
’ jack and the black
test lead to the ‘COM’ jack.
2. Set the Function Selector switch to the
:
ҏfunction.
3.Press the blue Second Function button twice to select the 
function.
4.Ensure there is no power applied to the circuit, and then connect the red test lead to the anode side and the black test lead to the cathode side of the diode being tested.
5.Read the Forward Voltage (Vf) on the instrument display.
Note: If the polarity of the test leads is reversed, the display will read ‘OL’. This can be used to determine the anode and cathode terminals of a diode.
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4.0Control Functions:
4.1Function Selector Rotary Switch
The rotary switch turns power on to the instrument and selects the function to be measured. The primary functions available are printed in red and white on the instrument scale. Alternate functions, accessed in conjunction with the blue Second Function Button, are printed in blue.
4.2Range Button
The instrument powers on in the Auto Range mode, as indicated by the ‘AUTO’ indicator in the display. To select a Manual Range, press the RANGE button which will lock the meter in its’ present range and bring on the MANU’ indicator in the display. Each subsequent press of the RANGE button circulates the instrument to the next higher range or wraps from the highest back to the lowest range. To exit the Manual Range mode and return to Auto Range, press and hold the RANGE button for one second.
4.3MAX/MIN Button
The Maximum and Minimum values are the highest and lowest values displayed during the time the instrument is in the MAX/MIN mode. To display Maximum and Minimum values, first ensure the value will not exceed the measurement range selected. Press the MAX/MIN button once to display the Maximum value, as indicated by the ‘MAX’ indicator in the display. Press it again to display the ‘MIN’ value and indicator. Press it once more to display the current value. In this selection, the ‘MAX/MIN’ indicator will flash. To exit the MAX/MIN mode, press and hold the MAX/MIN button for one second.
4.4Data Hold Function
To hold the current measured value, press the HOLD button. Press the HOLD button again to release the held data and return to continuous reading.
4.5Peak Hold Function
This instrument is equipped with a 1ms Peak capture capability in the ACA, ACV, DCA and DCV ranges. The Peak values are the highest and lowest transient values captured by the instrument, regardless of whether or not they might be displayed in the normal measuring mode. To display Peak values, first ensure the value will not exceed the measurement range selected. The instrument must then conduct an internal self- calibration, which calculates and stores the offset voltage in preparation for capturing a high speed Peak value.
To invoke the calibration operation, press and hold the PEAK button for approximately 2 seconds until ‘CAL’ appears in the display. The instrument is now calibrated to properly capture Peak values.
Press the PEAK button again to display the Maximum Peak, as indicated by the ‘PMAX’ indicator in the display. Press it once more to display the ‘PMIN’ value and indicator. Press and hold the PEAK button for 2 seconds to exit the Peak mode.
Note: The instrument must be calibrated in accordance with the above procedure whenever the function range is changed.
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