The flow chart for the current sensor shown in Figure 37 follows a similar path as the voltage sensor but this time the current that is output by the solar panel is what needs to be measured, and therefore it is done a little differently. The output of the panel is connected in series with a shunt resistor. These resistors typical have a low resistance that is around the milli-ohms. The purpose here is not to block the flow of current coming out the solar panel by placing a higher resistor value; instead, it is important that the current flows as freely as possible so that an accurate reading can be recorded. The focus is to let as much as current through as possible with a very little resistance so that just a small voltage drop is generated across the shunt resistor and then monitored by the AD8215. Since the voltage across the shunt resistor is too small to be used for actual measurements in a device, this voltage is amplified by the AD8215 by about twenty times. Once the voltage has being amplified, the output generated by the AD8215 chip is now useful for actually readings purposes.