Product Introduction:

1.Model: AMM-TE
2.PCB Size: 70.6*39mm  
3.Display Window Size: 51*24mm
4.Operating Voltage: DC 5V
5.Operating Current: 35mA
6.Measurement Precision: +/-1mA
7.Measurement Range: 0-2A
8.Overrange Display: the first bit displays 1 or -1
9.Display Color: Red

Packing List:

Circuit Diagram:

Circuit Principle:

AMM-TE ammeter is mainly composed of ICL7107, power circuit, reference voltage source,
input circuit and display circuit.
▲1. ICL7107 is a BCD output integral type A/D conversion chip, its internal includes; linear amplification, analog switch, oscillation, display driving etc.
▲2. Power circuit is divided into positive power and negative power; positive power is input by J2,C8 filtering; negative is composed of R8,Q1,L1,C6,C7,D2,D3 and ZD1, and generate -5V voltage is input by chip 26th pin.
▲3. Reference voltage source is composed of R1,R2,VR1,R9 and U2; 36-pin is reference voltage input pin; adjust VR1 potentiometer to let 36-pin voltage be 100mV.
▲4. Input circuit is composed of J1,R5,R6 and C3. When the current of measured circuit passes through R5, it will generate a voltage on R5; this voltage will be input to chip 31-pin through R6 current limiting and be processed; C3 is input voltage filtering capacitor.
▲5. Display circuit is composed of DS1-DS4,D1,D4;4 digital tubes can be drived directly by the chip, R10 is current limiting resistance of DS1-DS3 digital tubes decimal points.

Finished Product Debugging:

1. After connecting with DC 5V (please notice the polarity), the digital tube will display -.000 or .000,this is normal.
2. Use multimeter to measure the voltage between chip 36-pin and 35-pin,and adjust VR1 potentiometer let it be 100mV

Key Points Voltage Reference Value:

1.Chip 1-pin and 21-pin voltage 5V
2.Chip 36-pin and 21-pin voltage 100mV
3.Chip 26-pin and 21-pin voltage -5V

I. Tested by ICStation's Outstanding Partner ELECTROJUANYU:

Learn More Details in the Video:
(The language in the video is Spanish)

II. Tested by ICStation's Outstanding Partner arduinoLab:

Learn More Details in the Video:
(The language in the video is Russian)