I buy theese cheap AC meter on amazon and ebay his accuracy is not bad and not good +- 10V on 230V AC Voltage is not pretty but to much big. Current measurement accuracy is about 0.5A – 1A , It’s bigger tolerance. But no woory !!! these meters can you calibrate ,you can set accuracy for better values , both V and A ..
My video : How to improve accuracy of a measurement DDH303L AC voltmeter + ammeter
First step you must know the scheme diagram for DDH303L AC voltmeter + ammeter .
This is schematic :
Second step is choose small screwdriver , i choose flat 1.4mm for good setting two trimers one for voltage second for amperage
Step three is conect VA meter by diagram by first pictures diagram,
Warning !! circiut of Volt-ammeter do not conecting under voltage !!! 110V-220 is dangerous !!
1 Connect power suply 110 od 220V AC voltage
2 Connect load , Phase inserted through the toroid!
Step four See 2 holes :
Hole 1 is pot (trimer) for accuracy of measurement AC Voltage located at the green terminals (Power supply)
Hole 2 is pot (trimer)for accuracy of measurement AC Amps located under connector for toroid trafo.
Step five Take the screwdriver to turn the trimmer for amps or voltage
1 if you turn left values on volt – ammeter has been increase
2 if you tur right values on volt – ammeter has been reduced
Warning ! I have AC VA connected to power !! when turn pots with screwdriver , i see values for amperage and voltage on displey , but is dangerous !!!! be carefull!!!
If you not good electrician turn off from 220V 110V plug !! turn with trimers and turn on volt ammeter.
After calibration cann get reach better measurement accuracy , its work very precision work!
About DDH303L AC voltmeter + ammeter
This meter is suitable for measuring voltage and current in the sources, chargers, inverters.
Parameters of these volt-ammeters
- Working Mode: Voltage and current dual display,2-wires
- Measuring Range: AC100-300V, AC0.1-100.0A (with sensor transformer)
- Display: LCD, blue backlight, 3 digits;Accuracy: 1% +/- 2 digits
- Power Consumption: <0.2 VA;Can directly replace the 85L17 Analog current and voltage meter