Parallax Inc high-end current sensor module is located between the monitored system and its power input. It measures the voltage drop across a 100mohm series resistor and converts this analog value into a digital value that the microcontroller can read through the I2C serial bus. The power supply voltage is also measured and used as serial data. It operates over a temperature range of -40C to + 125C and comes with a plug and screw connector kit.