# Current-Voltage/ I-V Curve: explanation and use

The **current-voltage (I-V) curve** is generated during the flash test of a solar panel and depicts in a chart the relationship between electrical **current intensity (I) **and **voltage (V).**

## What are the technical parameters depicted in the I-V Curve?

**Current intensity**, expressed in amps, and **voltage (V), **expressed in volts, are the y-axis and x-axis in a graph depicting their relationship in **bipolar electrical devices**. In photovoltaics, the **maximum current** of a solar PV module is equivalent to **resistance R (= V/I)** of zero ohms in the circuit and is commonly referred to as the **short circuit current****(I _{sc})**. At this maximum point, the voltage V in the circuit is zero. Connecting the resistance, the voltage increases while the current intensity slightly decreases. Further increases of the resistance lead little increase in voltage but a current intensity of near zero. At maximum voltage, there is a break in the circuit, known as

**open circuit voltage (V**. The I-V curve depicts these two extremes in a graph with I

_{oc})_{sc }shown in the y-axis and V

_{oc}the x-axis.

## How to read the Current-voltage (I-V) curve?

Drawing the curve, there is only one point where at which **maximum power (Pm)**, expressed in watts, of the solar PV module is delivered. This break point is know as **maximum power point (MPP)**. The I-V data of a solar PV device cab be measured using various testing standards. The most commonly of these is** standard testing conditions (STC)** which is also the underlying standard of above sample I-V curve from a tested solar panel. STC specifies a clear sunny day with irradiance of 1,000 watts per square meter (1,000 W/ m²) and no shading.