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CZDANG's CY-20D is undoubtedly the smallest desktop multimeter you can buy. What's more, it can also talk, although you can disable this feature if you wish. |
Introduction to the CY-20D from CZDANG
What is so special about the CY-20D?
First of all, of course, the small size of this desktop multimeter. The front panel measures just 9.6 cm by 4.5 cm and the depth is 4.2 cm. This little meter is also designed so that the front panel is at a 45° angle and the display is easy to read.
Inside that small housing is a multimeter that allows you to measure DC and AC voltages, resistors, capacitors and temperatures. However, the CY-20D cannot measure currents.
A second notable feature is that the meter can speak the measured value clearly, although the volume could have been a little louder. This option can be switched on and off by means of a pushbutton.
Power is provided by an internal battery, which you can charge via a USB-C connector. No more changing batteries! Charging takes about two hours, after which you can use the meter for about eight hours.
Finally, there are only three pushbuttons, as the meter can set the most important measurement functions for you automatically.
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| The small size of th CY-20D multimeter. (© Banggood) |
Who is the manufacturer?
Packaging and scope of delivery
The appearance of the CY-20D
In the top of the case is the 'antenna' for picking up the electromagnetic field of the mains voltage. This is used in the 'NCV' measurement function where the presence of mains voltage can be detected without making contact. The underside is fitted with a rubber plate which, despite its low weight, makes the meter stable on the table.
The manual of the CY-20D
The red, round on/off button
The orange 'HOLD' button
The CY-20D is made by 'Shenzhen ChenZhou Technology Co. Ltd.', founded in 2016, a Chinese company that is part of 'ChenZhou Island Industrial Co., Ltd.'. The company focuses on the design, development, manufacture and sale of various products, including multimeters, soldering stations and hardware accessories. Its own (Chinese) website can be found at https://czdang.com.
Suppliers and prices
Suppliers and prices
The CY-20D is available for sale through well-known Chinese internet channels. We found the below bottom prices:
- Alibaba: $ 11.30
- Banggood: € 18.45
- AliExpress: € 11.69
Note
The CY-20D is offered under several other names. We found:
- CZD-20D also under the brand name CZDANG.
- ET20D under the brand name Tooltop.
- YX-820D under the brand name Yaxun.
The latter has a different appearance, see the picture below.
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| Yaxun's YX-820D version. (© AliExpress) |
Packaging and scope of delivery
The CY-20D comes in a sturdy cardboard box with the standard attributes that come with every cheap Chinese multimeter:
- Two 80 cm long fully insulated and very flexible test leads.
- A very cheap-looking one-meter thermocouple cable.
- A USB-C to USB-A charging lead of 30 cm.
- A miniature English-language manual.
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| The scope of delivery of this multimeter. (© 2025 Jos Verstraten) |
The appearance of the CY-20D
In the photomontage below, we have summarised the four main views of this little meter. In the right side are the two 4 mm banana plug sockets that form the input. In the left side is the USB-C connector for charging the battery.
In the top of the case is the 'antenna' for picking up the electromagnetic field of the mains voltage. This is used in the 'NCV' measurement function where the presence of mains voltage can be detected without making contact. The underside is fitted with a rubber plate which, despite its low weight, makes the meter stable on the table.
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| The views of the CY-20D. (© 2025 Jos Verstraten) |
The manual of the CY-20D
The supplied paper manual measures 10 cm by 6.5 cm and is virtually unreadable, that's how small the characters are. Fortunately, the manual is also available as a PDF on the internet. We have copied it to our account on Google Drive for easy downloading:
The specifications of the CY-20D
- Display: LCD monochrome screen, 40 mm x 20 mm
- Number of counts: 5999
- Measurement method: A/D conversion with double integration
- Sampling rate: approximately 3 times per second
- Measuring ranges DC voltage: 600 mV ~ 6 V ~ 60 V ~ 600 V
- Accuracy DC voltage: ±[0.5 % + 3 digits]
- Measuring ranges AC voltage: 600 mV ~ 6 V ~ 60 V ~ 600 V
- Accuracy of AC voltage: ±[0.5 % + 3 digits]
- Measuring ranges resistance: 600 Ω ~ 6 kΩ ~ 60 kΩ ~ 600 kΩ ~ 6 MΩ ~ 60 MΩ
- Resistance accuracy: ±[1.2 % + 3 digits] ~ ±[2.5 % + 3 digits]
- Measuring ranges capacitance: 1 nF ~ 10 nF ~ 100 nF ~ 1 μF ~ 10 μF
- Measuring ranges capacitance: 100 μF ~ 1 mF ~ 10 mF
- Accuracy capacitance: ±[3.5 % + 20 digits]
- Temperature measurement: -40 °C ~ 1,000 °C
- Temperature accuracy: ±[1.0 % + 4 digits]
- Diode measurement: yes, up to 3.2 V
- Data hold: yes
- Display illumination (backlight): yes
- Low-resistance buzzer measurement: yes, up to 50 Ω
- NCV measurements: yes
- Torch: no
- Automatic switch-off: yes
- Low battery indication: yes
- Power supply: 3.7 V ~ 200 mAh lithium-ion battery
- Dimensions: 96 mm x 45 mm x 42 mm
- Weight: about 110 g
Working with the CY-20D
Only three push buttons
The device has three push buttons, which have various functions.
The red, round on/off button
- Press for longer than two seconds:
Device switches on with automatic measurement mode activated or switches off. - Short press in automatic measurement mode:
Manually switches the measurement function in the order mVDC, mVAC, VDC, VAC, resistance, diode test, capacitance, temperature °C, temperature °F.
The orange 'HOLD' button
- Press briefly:
Switches the ‘HOLD’ function on or off, the measurement value freezes on the display. - Press longer than two seconds (until after the first beep):
The display illumination (backlight) switches on and off after about ten seconds. - Press for longer than three seconds (until after the second beep):
The display illumination (backlight) switches on and stays on until you switch it off by pressing this button for longer than two seconds. After switching on the backlight, the CY-20D is very clear to read thanks to its ideal position.
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| The very clear display after switching on the backlight. (© AliExpress) |
The orange 'NCV' button
- Press briefly:
Switches the 'NCV' function on or off. This 'Non Contact Voltage' function allows you to detect the presence of an electromagnetic field with the top of the device. As the field is stronger, the CY-20D beeps faster, more dashes appear on the display and red LEDs light up brighter. - Press for longer than three seconds (until after the second beep):
You enter talking mode, where the meter reads out the value in the display. The volume is actually a little too low to make this function really useful. Suppose you are measuring DC voltage and the display reads '0.020'. The meter then says 'DC zero point zero two zero volts'. You switch this function off by pressing this button for more than two seconds.
The automatic measurement mode
When the CY-20D is switched on, the display shows '----'. You can now measure resistances, DC voltages and AC voltages automatically. The electronics know how to distinguish these three quantities to be measured and the automatic mode works very quickly. Of course, there are limits to what the meter itself can detect. For instance, the device will not work if you put AC voltages smaller than 0.5 V at the input. Then you have to switch to the manual setting with the red button.
Automatic switch-off
The 'AUTO SHUT-DOWN' function switches the device off about fifteen minutes after the last action. Unfortunately, you cannot switch this function off.
The electronics in the CY-20D
Opening the housing
You need to remove the rubber strip glued to the bottom of the housing. This is because there are two of the four bolts underneath that you need to unscrew to open the housing. You can see the result in the picture below.
The entire electronics are on a PCB measuring only 86 mm by 37 mm! That PCB is screwed to the front plate of the multimeter. In the other half of the housing, you can see a metal plate that makes the meter slightly heavier and therefore more stable. The loudspeaker and the battery are glued to that plate. Above is another metal plate that serves as the 'antenna' for the 'NCV' function.
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| The insides of the CY-20D. (© 2025 Jos Verstraten) |
The PCB in detail
The picture below presents the PCB. As is immediately noticeable, the designers did not pay much attention to the protection of the internal circuit. The positive measurement input, on which the specifications allow a maximum of 600 V, goes directly to two MELF resistors R6 and R6A. No insulation slots around this track! A second resistor divider R9A, R9B and R9C is apparently in parallel with the MELF resistors and is composed of small SMD resistors. The transistors Q4 and Q5 undoubtedly form the primary protection against the occurrence of too high voltages in the internal electronics. A second safeguard is the green component on the edge of the PCB. This is a PTC that is also directly connected to the positive measurement input.
There is only one relay, which is the white block to the right of the PTC. To the left of the relay, you can see three strange white components marked with a green stripe. Those are three SMD LEDs that are switched on during 'NCV' measurements. The larger the detected field, the more of those LEDs light up. On the outside of the housing, this is manifested by an increasing intensity of red light shining out through a small hole.
The right part of the PCB contains the components for generating the necessary supply voltages and for battery management.
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| The PCB of the CY-20D in detail. (© 2025 Jos Verstraten) |
Testing CZDANG's CY-20D
Introductory note
In the following tables, values of a voltage, resistor or capacitor to be measured are given in the leftmost column. You should not regard these as absolute and thus not use them to judge the accuracy of the CY-20D. 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
We use various DC voltage sources and resistance dividers to monitor a range from 10 mV to 600 V. As you can conclude from the table below, the CY-20D 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 of 10 V without and with an accurate 1 MΩ resistor in series. Without this resistor, the CY-20D measures a voltage of 9.98 V, with the resistor a voltage of only 4.54 V. Over the 1 MΩ resistor, a voltage of 5.44 V falls. From these data, the input resistance of the CY-20D can easily be deduced: 834 kΩ.
This is remarkable, because the manual mentions the standard value of 10 MΩ. To check, we measure the input resistance in the switched-off state with the Fluke 8842A. This gives a value of 832.9 kΩ. So the data in the manual are not correct! In fact, such a resistance is far too low for a digital universal meter with a reading of 5999 counts. The low resistance causes a substantial error when measuring in high-impedance circuits that makes the indication on the rightmost digit meaningless.
Measuring 50 Hz AC voltages
We use our function generator DG1022 and a variac to generate 50 Hz sine wave voltages between 10 mV and 280 V. All 50 Hz AC voltages are measured with good accuracy.
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| Accuracy when measuring 50 Hz AC voltages. (© 2025 Jos Verstraten) |
The bandwidth when measuring AC voltages
To test this, we put a 1 Vrms sine wave voltage at various frequencies to the inputs of the CY-20D. We of course compare again with our ET3255. As follows from the table below, you can accurately measure up to 2 kHz.
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| The bandwidth in AC voltage measurements. (© 2025 Jos Verstraten) |
Measuring resistors
For this test, we have at our disposal a set of reference resistors with a tolerance of ±0.01 %. In addition, we measure a few less accurate resistors in the very low and very high ranges. 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 CY-20D. 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 cannot be compensated with the CY-20D. The results are again summarised in a clear table.
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| Accuracy when measuring resistors. (© 2025 Jos Verstraten) |
Measuring capacitors
Thanks to a set of five accurate capacitors with a tolerance of ±1.0 % and a pair of reference capacitors with a tolerance of only ±0.05 %, we can accurately map the performance of the CY-20D 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 noticeable is that the CY-20D measures small capacitors quite inaccurately. This is not exceptional for a low-cost device that measures capacitors using the two-wire technique. Measuring large electrolytics takes a long time. The CY-20D needs five seconds before the reading stabilises when measuring an electrolytic capacitor of 100 μF. For our test elco with a value of 10 mF, it takes even 12 seconds to put a stable value on the display.
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| Accuracy when measuring capacitors. (© 2025 Jos Verstraten) |
Measuring temperatures
The CY-20D is a fun and cheap gadget that also measures accurately in most measurements. The fact that this little meter also has a voice interface on board is something that you can undoubtedly surprise friend and foe with. However, take into account the low input resistance and therefore think carefully about when you can or cannot use the CY-20D.
It is a pity that measuring electrolytic capacitors is so time-consuming. That this does not have to be the case is proven by other cheap multimeters that we tested, which are capable of measuring such components quickly.
However, we have one major reservation. Do not use the CY-20D for performing measurements in 230 V networks. The internal protection is inadequate for this. Use the CY-20D on your workbench as a second (or third) meter for monitoring less critical voltages in your experimental low-voltage circuits.
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CZDANG CY-20D mini-desktop multimeter
This accuracy is not so easy to measure! We have come up with the following measuring setup. In the side of a large aluminum 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 CY-20D into that hole. We use our Fluke 52 meter as a reference. We also push the two thermocouples of this meter into the hole. The three thermocouples are therefore at the same temperature. We clamp a 100 W wire-wound resistor to the heatsink and connect it to an adjustable power supply. In this way, we can slowly increase the temperature of the heatsink.
We note the readings of both meters. The table below shows that the CY-20D also performs well in this area.
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| Temperature measurement with the CY-20D and the Fluke 52. (© 2025 Jos Verstraten) |
Our verdict on the CY-20D from CZDANG
The CY-20D is a fun and cheap gadget that also measures accurately in most measurements. The fact that this little meter also has a voice interface on board is something that you can undoubtedly surprise friend and foe with. However, take into account the low input resistance and therefore think carefully about when you can or cannot use the CY-20D.
It is a pity that measuring electrolytic capacitors is so time-consuming. That this does not have to be the case is proven by other cheap multimeters that we tested, which are capable of measuring such components quickly.
However, we have one major reservation. Do not use the CY-20D for performing measurements in 230 V networks. The internal protection is inadequate for this. Use the CY-20D on your workbench as a second (or third) meter for monitoring less critical voltages in your experimental low-voltage circuits.
CZDANG CY-20D mini-desktop multimeter