Curve tracers vary a parameter and measure another to analyze the characteristic curves of discrete semiconductor devices such as diodes, transistors, and thyristors. There are three types of products: current-voltage (IV), capacitance-voltage (CV), and ultra-fast transient or pulsed current-voltage (Fast IV). With IV curve tracers, for example, the voltage is varied and the current is measured. Product specifications and features for curve tracers include time sampling, list sweep, and multichannel sweep. In addition to semiconductor device curve characterization, these products are used in semiconductor failure analysis.