SparkFun Current Sensor Breakout

INA169 - SparkFun Electronics

The INA169 is a “high-side current monitor,” which means that you place a resistor (a “shunt resistor”) on the positive power rail and the INA169 measures the voltage drop across that resistor. The INA169 outputs a small current based on the measured voltage drop. If you place a resistor from the output of the INA169 to ground, you can measure the voltage at the output.