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With the introduction of the 189C, WinAPEX has taken a daring step in redefining multimeter functionality and operation. But now electronics hobbyists have yet to accept it (or not!). |
Introduction to the 189C multimeter from WinAPEX
What is WinAPEX?
A not so well-known brand marketed by Chinese company 'Shenzhen Hanyan Electronic Technology Co., Ltd.' from (of course) Shenzhen. The company specialises in developing digital multimeters, digital earth resistance meters, digital current clamps and infrared thermometers. The multimeters are sold under the name WinAPEX through internet channels such as Banggood and AliExpress.
What is so special about the 189C?
That is the innovative way you have to operate the multimeter. It is a typical handheld meter. You set the measurement function and the measuring range by turning a large disc fitted around the display. If you hold the meter in your hand, you can do so with your thumb. The manufacturer proudly calls that disc the 'Smart Rotary Dial'. What is 'smart' about that disc, however, is completely unclear. The measurement ranges are placed in the LCD display around this disc. A blue arrow indicates which measuring range is active. Moreover, you can also set the measuring range via the two upper green buttons below the circular disc.
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| Operating the 'Smart Rotary Dial' with your thumb. (© WinAPEX) |
Note
We also see this multimeter offered on the internet as 'Sunshine DT-24R'.
Suppliers and prices
The 189C can be ordered through well-known internet channels. At Banggood you will pay € 20.45 for it, at various suppliers on AliExpress the device costs € 27.99.
The packaging
The meter is supplied in a sturdy cardboard box, fitted with a plastic inlay in which the meter and measurement leads have found a good place to be protected from transport damage.
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| The packaging of WinAPEX's 189C. (© 2025 Jos Verstraten) |
The scope of delivery
In addition to the meter, there are three leads in the box:
- Two very flexible test leads that are about one metre long and have fully insulated banana plugs at one end and fully insulated test pins at the other.
- A rather cheap-looking thermocouple test lead with a type-K thermocouple at one end and two extremely rudimentary banana plugs at the other. This could have been much better! The solid pins fit into the multimeter's sockets with a lot of difficulty, and when pulling these banana plugs out again, you have to apply quite a bit of force, running the risk of pulling the thin wires from the plugs.
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| The delivery scope of WinAPEX's 189C. (© Banggood) |
The manual of the 189C
This is a very well-crafted booklet of eighteen pages in A6 format, describing in good English all the features of this multimeter. We have scanned this booklet and saved it on our account at archive.org, from which you can download it:
The specifications of the 189C
- Display: Colour LCD
- Number of counts: 5999
- Measurement method: A/D conversion with double integration
- Sampling rate: approximately 3 times per second
- Measurement ranges DC voltage: 600 mV ~ 6 V ~ 60 V ~ 600 V ~ 1,000 V
- Accuracy DC voltage: ±[0.5 % + 3 digits] ~ ±[1.0 % + 10 digits]
- Measuring ranges AC voltage: 6 V ~ 60 V ~ 600 V ~ 750 V
- Accuracy AC voltage: ±[0.8 % + 5 digits] ~ ±[1.2 % + 10 digits]
- Measuring ranges DC current: 600 mA ~ 6 A ~ 20 A
- Accuracy DC current: ±[1.2 % + 8 digits] ~ ±[1.5 % + 10 digits]
- Measuring ranges AC current: 6 A ~ 20 A
- Accuracy AC current: ±[2.0 % + 5 digits].
- Measuring ranges resistance: 600 Ω ~ 6 kΩ ~ 60 kΩ ~ 600 kΩ ~ 6 MΩ ~ 100 MΩ
- Accuracy resistance: ±[0.8 % + 5 digits] ~ ±[5.0 % + 30 digits]
- Measuring ranges capacitance: 6 nF ~ 60 nF ~ 600 nF ~ 6 μF
- Measuring ranges capacitance: 60 μF ~ 600 μF ~ 6 mF ~ 60 mF
- Accuracy capacitance: ±[3.5 % + 20 digits] ~ ±[5.0 % + 10 digits]
- Measuring ranges frequency: 6 Hz ~ 60 Hz ~ 600 Hz ~ 6 kHz ~ 60 kHz
- Measuring ranges frequency: 600 kHz ~ 6 MHz ~ 10 MHz
- Accuracy frequency: ±[0.1 % + 3 digits]
- Temperature measurement: -200 °C ~ 1,300 °C
- Diode measurement: yes, up to 4.0 V
- Low-resistance buzzer measurement: yes
- NCV measurements: yes
- Identification phase/neutral wires: yes
- Torch: yes
- Automatic switch-off: yes
- Low battery indication: yes
- Power supply: two 1.5 V AA batteries
- Dimensions: 153 mm x 70 mm x 33 mm
- Weight: about 200 g
The 189C from WinAPEX viewed in detail
The 'Smart Rotary Dial' and the display
These are obviously the most important parts of this multimeter, which is why we have clearly highlighted them for you via the picture below. The rotary dial has 26 positions and has a diameter of 67 mm. In the picture below, the blue arrow is on the 'AUTO' position (12 o'clock position). This is the meter's start-up position. For some measurement quantities, such as voltage, current and resistance, you can manually set the measurement range to all available ranges. For other quantities, such as capacitance and frequency, only one position is available and you have to rely on the meter's automatic range switching.
Of course, the dial is not linked to an old-fashioned mechanical switch. It is an encoder, which sends pulses in a certain order to the processor when turning left or right.
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| The 189C's dial and display. (© 2025 Jos Verstraten) |
The front of the meter
The picture below shows the front panel of the meter. The meter has a maximum width of 70 mm and a height of 153 mm. The depth is 33 mm. The device has five push buttons for operation.
- The red round button:
Turns the meter on and off and returns to the 'AUTO' position if you had first set a measurement range manually by turning the disc. - The two upper green buttons:
Short presses on these buttons allow you to do the same as turning the disc, i.e. select a measurement range. A longer press on the right button switches off the irritating beep after each operation of the meter. If you set the meter to the '750 Vac' position, you can measure the mains frequency by pressing the left button longer. This option is sensitive, it suffices to hold the 189C against a wall socket to see the mains frequency appear on the display in the format '50.00'. - The lower left green button:
After a short press, switch on the well-known 'REL' function. The currently measured value is subtracted from subsequent readings. After a longer press on this button, the white LED in the top of the meter lights up. If you set the meter to the 'Temp/Hz' position, pressing this button allows you to switch between measuring temperature in °C, measuring temperature in °F or measuring the frequency of the input signal in Hz/kHz/MHz. - The lower right green button:
A short press on this button activates the 'HOLD' function, freezing the reading on the display. By pressing slightly longer, this button allows you to adjust the intensity of the LCD display in five steps.
Three 4 mm female banana socket are located at the bottom of the meter:
- 20A
- COM
- VΩ
You must use the '20A' input for all current measurements. By the way, you can see which inputs to use in the display below the measured value.
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| The 189C's front panel. (© Banggood) |
The back of the meter
In the back of the meter is just the battery compartment where two 1.5 V type AA batteries belong.
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| The back of the 189C. (© Banggood) |
What strikes us about the 189C
- Unlike most Chinese multimeters, the 189C does not come with a soft silicone jacket for protection. Probably the dial gets in the way of such an attribute.
- The 189C does not have a fold-out backrest and thus cannot be placed at an angle on your workbench. This, of course, has everything to do with the location of the three input sockets on the underside of the meter.
- To open the battery compartment, you need a screwdriver. Not very handy!
- What is very handy is the fact that you can replace the built-in fuse via the battery compartment.
- When you switch the meter on, it always enters the 'AUTO' mode. You can then measure DC voltages, AC voltages and resistors. The meter even recognises a 1 Ω resistor between its inputs and then switches to resistance measurement.
- The 'AUTO' mode disappears when you turn the ring or press one of the top green buttons. You can then manually set a measurement range. Briefly pressing the red button returns the 189C to the 'AUTO' mode.
- In 'DIODE' mode, the open-input voltage is 3.98 V. You can therefore test all types of LEDs with this meter.
- The range switching works a bit strangely. From low to high, the meter switches at a display value of '6.099' to '06.10'. From high to low, however, the meter switches from '05.98' to '5.889'.
The electronics in the 189C
Opening the housing
After removing four small screws at the back of the 189C, you can separate the two halves of the housing. The rear half contains only the battery compartment, which makes contact with two large pads on the PCB via two spring-loaded copper strips.
The circuit board of the 189C
In the picture below, you can see the large PCB attached to the front of the enclosure. At the very bottom, there are three 4 mm banana connectors soldered directly to the PCB. A little higher up, you can find a constantan bracket. This is obviously the shunt resistor that the meter uses to convert the measured current into a voltage. Above this shunt you can see the standard silica sand-filled glass fuse of 20 A. As already written, you can replace this fuse via the battery compartment, a very handy feature of this meter.
To the left of this fuse is the 189C's only relay. Above this relay, you can see five MELF resistors that obviously form the primary voltage divider of the input circuit. The input circuit is protected by the green component next to the relay, undoubtedly a PTC resistor, and by the transistors present next to the MELF resistors.
Such protection is now standard in most cheap Chinese multimeters and we leave it to the experts in this field to decide whether this protection is good enough for the meter to be labelled 'CAT III 600V'. It is worth noting that nowhere on the meter is the CE symbol present.
Above the two large pads that contact the battery you will find the only chip that is recognisable. That is an LCD driver HT1621B from Holtec.
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The circuit board in the 189C. (© 2025 Jos Verstraten) |
Testing WinAPEX's 189C
Introductory note
The following tables list values of a voltage, current, resistance or capacitor in the leftmost column. You should not regard these as absolute and thus not use them to assess the 189C's accuracy. Hence the symbol ‘≈’ in front of these values. For assessing accuracy, the right-hand columns serve with comparative measurements with our much better laboratory equipment.
Measuring DC voltages
Here we use various DC voltage sources and resistance dividers to cover a range from 1 mV to 1,000 V. As you can conclude from the table below, the 189C measures DC voltages extremely accurately. We use our Fluke 8842A as a reference. The system that automatically selects the correct measurement range works extremely quickly.
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| Accuracy in measuring DC voltages. (© 2025 Jos Verstraten) |
The input resistance when measuring DC voltages
To assess this parameter, we measure a stable DC voltage without and with an accurate 1 MΩ in series. Without this resistor, the 189C measures a voltage of 13.63 V, with the resistor it measures a voltage of 12.39 V. A voltage of 1.24 V therefore falls across the 1 MΩ resistor. From these data, the input resistance of the 189C can be easily deduced: 9.992 MΩ.
Measuring DC currents
We form a series circuit of a DC power supply with digitally adjustable current, the 189C and our reference meter ET3255 from EastTester. The measurement results are again summarised in the table below. No doubt you will agree with us that there is little to comment on here!
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| Accuracy in measuring DC currents. (© 2025 Jos Verstraten) |
The burden voltage when measuring DC currents
The burden voltage is the voltage that falls across the meter when you measure a current. The smaller this voltage, the less influence measuring a current has on the circuit in which you are measuring. For a current of 5 A, a voltage of 100.4 mV falls across the meter's inputs.
Measuring resistors
For this test, we have at our disposal a set of reference resistors with a tolerance of ±0.01 % plus some less accurate ones. As a reference meter, we obviously use our 8842A from Fluke. This meter uses a four-wire kelvin probe, which is not possible with the 189C. When measuring very low resistances, the resistance of the test leads and the resistances of the contacts in the input sockets obviously play a major role. These can fortunately be compensated in the 189C with the 'REL' function. The results are again summarised in a clear table.
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| Accuracy when measuring resistors. (© 2025 Jos Verstraten) |
Measuring 50 Hz AC voltages
We use our function generator DG1022 and a variac to generate 50 Hz sine voltages between 10 mV and 260 V. An AC voltage of 10 mV is not recognised by the 189C and the display remains at zero. However, all other 50 Hz alternating voltages are measured with good accuracy.
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| Accuracy when measuring 50 Hz AC voltages. (© 2025 Jos Verstraten) |
Measuring capacitors
Thanks to a set of five accurate capacitors with a tolerance of ±1 % and a pair of reference capacitors with a tolerance of only ±0.05 %, we can accurately map the 189C's performance when measuring such components. Above 1 µF, we measure ordinary electrolytic capacitors from our stock. As a reference meter, we use EastTester's ET4401 with an accuracy of ±0.2% for non-electrolytic capacitors. What is striking is that the 189C is able to measure even small capacitors quite accurately. This is exceptional for a low-cost device that measures capacitors using the two-wire technique.
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| Accuracy when measuring capacitors. (© 2025 Jos Verstraten) |
The bandwidth when measuring AC voltages
To test this, we feed the 189C with a 1 Vrms sine wave signal at various frequencies. We compare again, of course, with our ET3255. You can accurately measure up to 3 kHz.
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| The bandwidth in AC voltage measurements. (© 2025 Jos Verstraten) |
Measuring frequencies
In this test, it is not only the range that is interesting, but also how large the voltage must be to get a stable indication of the signal's frequency. The table below shows that you need a signal of about 350 mV to measure its frequency between 10 Hz and 1 MHz. At higher frequencies, sensitivity decreases quite rapidly.
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| Sensitivity when measuring frequencies. (© 2025 Jos Verstraten) |
Measuring temperatures
This accuracy is not so easy to measure! We have created the following measurement setup. In the side of a large aluminium heatsink we drill a 1.5 cm deep hole of 3 mm diameter. We fill this hole with heat-conducting paste and push the tip of the thermocouple supplied with the 189C into that hole. We use our Fluke 52 meter as a reference. We also push the two thermocouples from this meter into the hole. So the three thermocouples are at the same temperature. We clamp a 100 W wire-wound resistor onto the heatsink and connect it to an adjustable power supply. In this way, we can slowly increase the temperature of the heatsink. We record the readings of both meters.
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| Measuring setup for determining temperature measurement accuracy. (© 2025 Jos Verstraten) |
The table below shows that the 189C also performs exceptionally well in this area.
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| Temperature measurement with the 189C and the Fluke 52. (© 2025 Jos Verstraten) |
Our opinion of WinAPEX's 189C
In terms of measurement accuracy, there is nothing to complain about with this multimeter. In our tests of other cheap multimeters, there is always a measurement range we are not so satisfied with. That is not the case with this 189C. You can be confident that any measurements you make with this meter will produce a result that is more than accurate enough for the average electronics hobbyist. The input resistance of 10 MΩ is excellent and so is the burden voltage of only 100 mV at 5 A. It is worth noting that the 189C also measures small capacitors satisfactorily, which is not the case with all cheap multimeters.
We dare not judge the uniqueness of this meter, its operation with the 'Smart Rotary Knob' vaunted by the manufacturer. If you are used to multimeters with rotary knobs, switching to operating a meter with such a large, thumb-operated ring will take some getting used to. Whether you choose to do so is a matter of personal preference. But after some fiddling with the meter, adjusting with the dial is very intuitive and easy. This is undoubtedly also due to the fact that after a while you know where the various measurement ranges are located on the circle, so you no longer have to search.
We do not give our own opinion on this operating method because we are not used to working with handheld meters anyway. We measure with large, rugged push-button-operated desktop meters such as the Fluke 8842A and working with every handheld meter we tested takes quite a bit of getting used to.
WinAPEX 189C multimeter
