Chroma - Milliohm Tester (Updated: 23 May 2022)


Chroma 16502 Milliohm Tester
Chroma 16502 Milliohm Tester

The Chroma 16502 Milliohm Meter is Chroma's newes t digital Milliohm Meter. 0.001mΩ~1.9999MΩ wide measurement range. DC, Pulsed, and Dry-circuit test current driving modes, enable the Chroma 16502 can be properly used in DC resistance measurement for various inductive components (coil, choke, and transformer winding etc.), cable, metallic contact (connector, relay switch etc.) and conduction materials.

Using the A165014 Temperature Compensation Card with A165015 PT100 Temperature Probe, res i s tance values measured at ambient temperature can be corrected by applying a thermal coefficient so that the display shows the corresponding resistance values at any other temperature with temperature correction function. Temperature increase (Δt) is obtained and di splayed by conver t ing res i s tance measurements and ambient temperature with convenient temperature conversion function. This function is especially useful for verifying motor windings or coils, where the maximum temperature increase needs to be determined when current is applied.

Key Features

  • Basic accuracy : 0.05%
  • Pulsed test current output mode is used to reduce thermal EMFs affection on milliohm measurement
  • DC test current output mode is used to fasten measurement speed for inductive DUT
  • Dry-circuit test current output mode (limited Max. 20mV) is used to measure such contact resistances where the maximum open-circuit voltage must be limited to 50mV
  • Temperature correction (TC function) regardless of material or temperature
  • Useful temperature conversion function for motor/ coil evaluation
  • 4 channels R scan with balance check function for fan motor (combined with A165017 option)
  • 0.001mΩ~1.9999MΩ wide measurement range with 4½ digits resolution
  • Standard RS-232 interface
  • Optional GPIB & Handler interface
  • Bin-sorting function
  • Comparator and pass/fail alarming beeper function
  • Large LCD display (240 x 64 dot-matrix)
  • Friendly user interface
  • LabView® Driver

Dry Circuit

Dry circuit test limits open-circuit voltage level to avoid any damage on contact junction while initial of contact for contact resistance measurement. The Chroma 16502 limits this open-circuit voltage level to be lower than 20mV.

R Scan


4 channels R scan with balance check function for fan motor (combined with A165017 option). Fan and motor are combined by multiple groups of coils and should be inter-balanced between coils or it may cause abnormal sound. Thus, test if the coils balance is needed. The 16502 provides R scan function plus option A165017 4 channels R scanner for customer test. For measurement more accuracy, the customer can use it with temperature compensation function. R Scan function should be coordinated with purchased option A165017 4 channels R scanner


Selection of comparator function ON and OFF. The limit can be set to single Upper or Lower, and both, depends on the test requirement. Two setting methods are available: absolute value (upper/lower limit setting) and relative value (% of a reference value), and judgment results, indicated by Hi, PASS or Lo and beeper, are also output via Handler I/F, RS-232 and GPIB interfaces.

Bin Sorting

According to a preset range, measurements can be classified in up to ten ranks (BIN1 through BIN8, BIN0 and BIN OUT is over or lower limit). Setting are the same as for the comparator, using either absolute or relative values with results displayed and output to Handler I/F, RS-232 and GPIB interfaces.

Meas. Delay


Delay time between the test signal start output and the measurement.Generally used for DUT needs more time for charge. For some large inductance component testing, trigger delay time must be set to delay the measurement start point till test current is ready

Trig. Delay

Delay time between the test start and the external trigger. Generally used for automatic equipment timing adjustment or delay time for waiting a real leakage current


Eliminates the measurement error caused by leakage current of outside test jigs and oset voltage of inside circuit.


Measurement values can be averaged to minimize display instability. The display shows the average value over a period. The number of samples to average can be set from 01 to 10

Power Noise Filter

The measurement of micro current is easily interfered by power noise. The Chroma 16502 used advanced power noise filtering technology to filter the selected line frequency noise accordingly for accurate measurement.

Basic Performance

Parameters / Characteristics Specifications
11200 (650V)
Range Basic Measurement Accuracy;
Test Current
20mΩ ±(0.1% of reading + 0.03 % of range) ; 1A typical
200mΩ ±(0.05% of reading + 0.03 % of range) ; 100mA typical
±(0.05% of reading + 0.03 % of range) ; 10mA typical
20Ω ±(0.05% of reading + 0.03 % of range) ; 1mA typical
200Ω ±(0.05% of reading + 0.02 % of range) ; 1mA typical
2kΩ ±(0.05% of reading + 0.01 % of range) ; 1mA typical
20kΩ ±(0.1% of reading + 0.01% of range) ; 100µA typical
200kΩ ±(0.2% of reading + 0.01% of range) ; 10µA typical
2MΩ ±(0.3% of reading + 0.01% of range) ; 1µA typical
Test Signal Drive Mode DC+, DC-,Pulsed+, Pulsed -, Pulsed ±, Stand by
Dry Circuit Open Circuit Voltage less than 20mV; for 200mΩ, 2Ω, 20Ω ranges only
Measurement Time Fast 65ms
Medium 150ms
Slow 650ms
Temp. Correction / Conversion Function Temp. Measurement Accuracy (Option) -10.0°C ~ 39.9°C ±(0.3% of reading+0.°C) 
40.0°C ~99.9°C ±(0.3% of reading+1.0°C) 
Temp. Sensor Type (Option) PT100/ PT500
Interface & I/O Interface RS-232(Standard) , GPIB, Handler (Optional)
Output Signal Bin-sorting & Pass/Fail judge
Comparator Upper/Lower limits in value
Bin Sorting 8 bin limits in %, ABS
Trigger Delay 0~9999ms
Trigger Internal, Manual, External, BUS
Display 240 x 64 dot-matrix LCD display
Correction Function Zeroing


Options Descriptions
Hardware Options 16502 Milliohm Meter
A110235 GPIB & Handler Interface
A110236 19" Rack Mounting Kit
A113012 Vacuum Generator for A165018
A113014 Vacuum Pump for A165018
A165013 GPIB and Handler Interface with Temperature Compensation
A165014 Temperature Compensation Card
A165015 PT100 Temperature Probe
A165016 Pin Type Leads (flat)
A165017 4 Channels R Scanner
A165018 Test Fixture for SMD Power Choke
A165019 Pin Type Leads (taper)
A165022 Four Terminal Test Cable

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