diff --git a/source/_integrations/derivative.markdown b/source/_integrations/derivative.markdown index d2957938614..6ad0f161a48 100644 --- a/source/_integrations/derivative.markdown +++ b/source/_integrations/derivative.markdown @@ -18,9 +18,8 @@ ha_platforms: ha_integration_type: helper --- -The derivative ([Wikipedia](https://en.wikipedia.org/wiki/Derivative)) integration creates a sensor that "smooths-out" another sensor (the **source sensor**). -Derivatives of the specified sensor will be averaged in a given time window with a Simple Moving Average algorithm weighted by time. This is, for instance, useful for a sensor that outputs discrete values or to filter out short-duration noise. -Derivative sensors are updated upon changes of the **source sensor**. +The derivative ([Wikipedia](https://en.wikipedia.org/wiki/Derivative)) integration creates a sensor that estimates the derivative of the +values provided by another sensor (the **source sensor**). Derivative sensors are updated upon changes of the **source sensor**. For sensors that reset to zero after a power interruption and need a "non-negative derivative", such as bandwidth counters in routers, or rain gauges, consider using the [Utility Meter](/integrations/utility_meter/) integration instead. Otherwise, each reset will register a significant change in the derivative sensor. @@ -83,7 +82,7 @@ unit: required: false type: string time_window: - description: The time window in which to calculate the derivative. By default the derivative is calculated between two consecutive updates without any smoothing. + description: The time window in which to calculate the derivative. Derivatives in this window will be averaged with a Simple Moving Average algorithm weighted by time. This is for instance useful for a sensor that outputs discrete values, or to filter out short duration noise. By default the derivative is calculated between two consecutive updates without any smoothing. default: 0 required: false type: time