Summary[]
The Taint Detector serves a similar function to the Vis Detector. When used to click on thaumic devices or conduits it will give you an indication of how much Taint they contain.
While the Taint Detector is in your inventory or hotbar it will display the level of Taint in your current chunk in the lower right-hand corner of the screen. If the dark sphere below the bar glows it indicates that the current chunk might increase it's Taint rating or possibly even lower it's Aura rating.
Craft (Infuser)[]
Source - Thaumcraft2 Wiki