Charge is the integral of current over time. The LTC4150 measures battery consumption and charging in handheld PCs and portable products. This device monitors the current flowing through an external sense resistor located between the battery's positive terminal and the battery load or charger. The voltage across the sense resistor is then obtained, and the signal is integrated in multiple stages to infer the charge level. This signal is output as pulses on the device's interrupt pin; the frequency of the pulses is the sense voltage, and the number of pulse cycles is the coulomb count. These pulses correspond to a fixed amount of charge flowing into or out of the battery, and the polarity indicates whether the battery is discharging or charging. Color: Material: PCB Package Contents: 1 * Coulomb Counter Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.