I buy digital Ammeter (ampermeter) from ebay and i cannot found schematic diagram for this .
After search i found several schematic for this ammeter
Module name: current display module
Measurement accuracy: 0.1%
Refresh rate: about 200ms
Display: three 0.56 “digital tube
Measuring range: 0A-10A
Power supply range: 4V-30V
Operating Current: less than 8mA
Storage Temperature: -10? to +65?
Input impedance: 5 milliohms
External dimensions: 48*29*26mm
Next ammeter is very simalar (maybee is the same) but muss have complete separated power supply !!! canot powering from “load source (battery)” If i connect power suply wires with mesauring wires ammeter burn !! 🙁 .. Power supply muss be complete separated !!!
Schematic diagram of digital ammeter with complete separated power supply:
Power supply is complete isolated from “power circuit” power suply can be DC supply with voltage 4.5V – 30V (7-28V).
My tips for better accuracy of digital ammeter from ebay !
Tip one is kalibration with potenciometer (trimer) you muss use little cross screwdriver and change pots.
I change pots under voltage i see curent “amps flow ” and check with another multimeter (ammeter) value showing on ammeter , change pots on ammeter values match with control multimeter.
Tip two is for case ammeter shows less than is real.
I’ll try to do a little notch on the shunt, but this tip i use only sometimes
My experiences with this ammeter is good ..All ammeter have low power consumion and good accuracy i use for car charger i see curent draw from charger to my car battery. For testing voltage on car batter i use “cigarette voltmeter”