AVR chips have 10-bit AD, so this module simulates a resolution of 0.00489V (5V / 1023), so the minimum voltage of input voltage detection module is 0.00489 Vx5 =0.02445V. The principle of voltage test based on principle of resistive voltage divider design, can make the red terminal connector input voltage to 5 times smaller. Analog input voltages up to 5 v,the voltage detection module input voltage not 5Vx5 = 25V (if using 3.3V systems, input voltage not 3.3Vx5 = 16.5V) This module can be used to test the current and voltage. The MAX471 chip on the board used to test the consume current of the load., Weight: 0.08598028218 pounds, Manufacturer: Hipzeepo