multimeters

see also:

• oscilloscopes

• multimeters are one of those must have devices every household should own
• they generally have a range of very useful functions:
  • measure voltages:
    • check if your batteries are flat including your car battery
    • check if your car's alternator is working (car battery voltage should be giving a voltage above 13V when car is running)
  • check for wire or circuit continuity
    • this will help confirm whether a wire is broken or disconnected
  • measure currents
  • check electronic components for resistance, capacitance, etc
• for more advanced capabilities an oscilloscope may be needed
• some multimeters also have a basic oscilloscope functionality
• some multimeters also have a “clamp current” functionality which is placed around ONE of the two (positive and negative) DC cables to measure current flowing through the cable
• some multimeters also include thermal imaging camera and screen

• these are used by campers usually between their 12V batteries and either charger device or a load device
• the most useful one for campers are those with 50A Anderson plugs on either side
• they all measure real time voltage, amps, watts, Ah and Wh
• some display max and min values
• do not have an inbuilt battery as not needed
• cheap unidirectional Chinese generic models
  • these have many different brandings but all seem to come from same factory or at least same manufacturing
  • they all seem to have the same fault - the Ah and Wh measurements are low by a factor of ~0.57!!
  • max Ah is said to be “65Ah” but this would equate with about 110Ah
  • as they are unidirectional, you must ensure the cables are connected correctly for your needs according to the load and source
• KWS-DC26 meter
  • these are twice the price but at least do not have the error of the above
  • bidirectional
  • also includes timer for how long power has been running through it and a thermometer probe and displays real time temperature
  • voltage: DC 8-80V ± 1%+0.5V
  • Current measurement range: 0-20A/25A/35A/50A ± 1%+0.2A
  • Power measurement range: 0-4000W ± 1%+2W
  • Electric energy range: 0-99999Wh
  • Ampere hour range: 0-9999Ah
  • Timing range: 99 days and 59 hours
  • Temperature: -20~99 ℃± 2%
  • available connectors: Anderson plug 50A; XT-60 25A; XT-90 35A; pin type 20A;
  • readily available on Aliexpress for ~$AU32 incl. GST, delivery
• other XT-30 / XT-60 meters
  • these have XT-30 or XT-60 connectors and allow for 5-40V or 8-150V, may have up to 64A metering and often have alarms for low voltage cutoff and over-current protection

• multitude of budget meters
  • eg. $AU20 or so
• Fluke 101
  • high quality compact basic meter with LCD display great for most household use; 2xAA batteries;
  • ~$AU100
• Fluke 117
  • high quality professional meter with LCD display;
  • very responsive beep to continuity
  • ultrasensitive NCV detection
  • current only goes down to 1mA
  • ~$AU370
• FNIRSI - DMT-99 Smart Digital Multimeter
  • USB-C charging; color screen;
  • “smart” as it auto detects the mode you are likely to be needing - voltage vs resistance only though
  • no temp probes but does display temperature
  • current goes down to 1microA
  • continuity beep is a bit slow in Auto mode but faster in direct diode mode;
  • capacitor testing is much slower than the Fluke 117
  • non-contact voltage sensor does not seem very sensitive
  • https://www.youtube.com/watch?v=609HDbbX-rg
  • https://www.youtube.com/watch?v=PfzVvXjNsL0 - advanced features
    • regular / recording oscilloscope-like (doesn't display a sine wave for AC though just the voltage) / monitoring mode uses thresholds but seems very limiting functionality
    • threshold settings voltage, current and temp (all min/max)
    • history record
    • auto shut off

• these additionally have a clamp mechanism which allows measuring current through a wire without connecting to it
• FNIRSI DMC-100
  • https://www.aliexpress.com/item/1005008221668394.html ~$AU70

• Fluke T6-1000 PRO Electrical Tester
  • measures voltage up to 1000 V ac and current up to 200 A ac, all through the open fork and without test lead contact to live voltage - but need to connect black lead to GND
  • works with most wire up to AWG 4/0 (17.8 mm/0.7” jaw opening)
  • 1 to 1000 V ac or dc; Resistance 1 Ω to 100 kΩ;
  • visual and audible continuity test;
  • does not do other usual multimeter tests (?no DC current)
  • ~$AU620

• see oscilloscopes

• great little device with lovely 3.5“ touch screen with 10-12hr battery life
• oscilloscope:
  • 10bit; 10MHz bandwidth; 50MSa/sec; 64K samples buffer; 100ns-50sec time scale with YT/Roll; AC/DC coupling;
  • voltage: 10mV-10V/div; 1MOhm input impedance; persistence function;
  • basic trigger on rise or fall, normal/auto/single;
  • FFT/ABS; single channel via MCX plug input; thus no X-Y;
• multimeter:
  • 600mV/6V/60V/600V/1000V DC ranges; 600mV/6V/60V/600V/750V AC ranges; max current 6A/10A; can measure AC and DC voltages simultaneously;
  • freq measurement range: 10Hz-60MHz but testing would not go above 20MHz; temp probe; banana plug inputs;
  • fast beeping on continuity testing
• signal generator: max 3V; sine/sawtooth/square/triangular; 1Hz-50kHz (plus additional 100kHz-200KHz for square); MCX plug output;
• ~$AU250 for DM40C with temp probes as well.
• https://www.aliexpress.com/item/1005008602842525.html
• https://www.youtube.com/watch?v=jYW1L7a9ipE
• https://www.youtube.com/watch?v=gRHr8QsTnQc

• great affordable jack of all trades oscilloscope/multimeter but has issues as could be expected for the price point
• no temperature measurement;
• oscilloscope:
  • 2ch; BNC; 50MHz; DC/AC coupling; 1x/10x probe; 150V/300V max input; 1.5-280MSa/s; 10ns-20s/div; 25000counts; 128kb record; 20mV-10V/div; usual trigger modes;
  • 3.5” 320×240 display; YT, XY, rolling modes;
• signal gen:
  • sine, square, sawtooth, half wave, full wave;
• see https://www.youtube.com/watch?v=kpzNVsSmUu0 Zoyi ZT-703S issues
  • state 50MHz but are only reliable below 40MHz
  • dysfunctional signal generator
    • max freq for sine is 5kHz
    • can't adjust freq for square in main interface, need to go to separate “app” interface to change freq - up to 500kHz
    • display of the dual outputs is very different
    • noisy
  • buggy software
    • need to ensure you are actually using the current current setting for the probe input - mA vs A else get erroneous readings without warning
    • the chart display in multimeter mode is pretty much useless - scale doesn't change
• https://www.aliexpress.com/item/1005008299861413.html ~$AU110

• dual ch 10MHz 9,999 counts but no FFT/maths, no X-Y
• 2MHz 0-3.3V signal generator sine, square, triangle, half wave, full wave
• temp measurement;
• 8hr 3000mAh battery; USB-C charging;
• ~$AU100
• https://www.youtube.com/watch?v=_jEodb8JLz4
• https://www.youtube.com/watch?v=m9SSgKhO23Y
• similar to the Zoyi ZT-703S but:
  • smaller, lighter
  • generally more clunky user interface - need to dig down into menus to change things
  • only 10MHz bandwidth
  • no X-Y mode
  • unable to freeze brief episodes
  • signal generator output is BNC
  • much better signal generator - up to 2Mhz, better user interface
  • stronger support bracket, additional hook hole on rear to hang it up
  • whilst Auto detect mode for multimeter is great, if you connect a 400V DC it will fry the resistor circuit even though it is rated to 700V as the Auto mode uses the resistor mode initially in its detection process
  • doesn't trigger on a single pulse?

• multimeter - essentially similar interface and function as the FNIRSI - DMT-99 Smart Digital Multimeter
• dual ch 50MHz 250MSa/sec, 19,999 counts, 32kb with FFT/maths, X-Y, auto/normal/single trigger modes, AC/DC coupling;
• 50KHz 0-3V signal generator
• 8hr 3000mAh battery; USB-C charging;
• insulated BNC connectors will not fit the BNC ports - you will need non-insulated BNC extension cables
• ~$AU120
• https://www.youtube.com/watch?v=_EX-CjUMEVg automotive CAN BUS use
• https://www.youtube.com/watch?v=lRzDVlNFxnU automotive use - captured the ignition coil waveform

• very versatile hobbyist unit with large 4.3“ touch display
• multimeter: Auto detect mode; max 1000V DC 10A, 760V AC 10A, and essentially similar interface and function as the FNIRSI - DMT-99 Smart Digital Multimeter
• oscilloscope: max 400V; dual ch 50MHz 250MSa/sec, 19,999 counts, 10nsec-10sec/div; 10mv-10V/div; 64kb with FFT/maths, X-Y, auto/normal/single trigger modes, AC/DC coupling; 1x/10x;
• signal gen 0-3V; 10MHz sine, 5MHz other waves; output is SMA port?
• no mention of cat rating for multimeter so perhaps avoid high voltages
• 4000mAh battery
• may have issues with insulated BNC connectors fitting as with the 2C53T model?
• https://www.aliexpress.com/item/1005008413762182.html ~$AU150
• https://www.youtube.com/watch?v=kBTBMTDlR3s
  • some jitter and noise with waveforms
  • multimeter history graph seems buggy
  • capacitance lower limit ~1nf
• https://www.youtube.com/watch?v=NjtfyVPaW70
  • multimeter is limiting; did not detect microA currents;
  • oscilloscope not showing correct frequency?

• very basic limited oscilloscope: no BNC inputs - multimeter probes are used instead; 5MSa/sec; 1MHz bandwidth;
• sliding cover for the USB-C charging port which when opened, closes the probe ports
• https://www.youtube.com/watch?v=3Y85wbjafzQ

• higher 60,000 count in multimeter mode than the HDS120 giving improved range for a given setting and improved resolution
• very basic limited oscilloscope as for HSD120: no BNC inputs - multimeter probes are used instead; 5MSa/sec; 1MHz bandwidth;
• sliding cover for the USB-C charging port which when opened, closes the probe ports
• https://www.youtube.com/watch?v=d9-kKOfWF98

• 3.2” display but no touch screen; 2500mAh battery;
• dual channel BNC osc; 120MHz bandwidth (half that in dual channel use) and 250MSa/s; FFT; Trigger; XY; 128Kb storage;
• 2.5V max 1Hz-2MHz signal gen
• multimeter: 750V max DC / 600V max AC; 10A max; resistance, capacitance, diode, continuity
• 600g;
• https://www.aliexpress.com/item/1005006545907549.html ~$AU135

• smartphone via BT for recording; USB-C charging and connect to PC;
• 2.8“ display; no current measurement by probes;
• 0-1000V AC/DC; 0-600A AC/DC; inrush current 0-600A; NCV;
• very basic oscilloscope: 1MHz bandwidth; 5MSa/sec; max. input 1000V; 2.5microsec-10s/div; 30mV-500V/div; only automatic trigger mode;
• https://www.aliexpress.com/item/1005008497882590.html ~$AU100

• https://www.youtube.com/watch?v=jnBjaK-gA0I
• https://www.youtube.com/watch?v=UEM5DYNbBYs
• 20A/200A/1000A ranges for clamp meter current 2000counts (20,000 counts for voltage)
• inrush mode but no single shot function
• only 1MHz bandwidth and highest sensitivity for current is 10A per division
• 18650 battery, draws 50-100mA
• BT iphone app can act as a data logger

• A version has 600A DC max; B version as 1000A DC max; NCV;
• 2.8” screen; smartphone app; 20,000 count range;
• USB-C charging;
• very basic oscilloscope: 1MHz bandwidth; 5MSa/sec; max. input 1000V; 2.5microsec-10s/div; 30mV-500V/div; only automatic trigger mode;
• https://www.aliexpress.com/item/1005009774780271.html ~$AU135

• see also thermal imaging cameras
• FNIRSI® TDM-120P Thermal Imaging Multimeter
  • 2026 model on special $192
  • 2.8“ 120×90 HD Imaging; <60mK High Thermal Sensitivity, 17micron pitch; 25Hz frame rate; emissivity 0.1-1 adjustable; 32Gb image storage;
  • Full Multimeter Functions: AC/DC Voltage, Resistance, Capacitance, continuity, diode;
  • 2.8” LCD Touch Screen | 7 Color Palettes | One-Click Save & USB Export
  • USB-C charging