## The Response Time

The response times mentioned on datasheets and specifications of leak detectors are the individual response times of the leak detectors without any test piece connected, or with just the reference leak connected and are valid only for leaktests with test pieces with very small volumes. The response time of a test arrangement is given by the volume divided by the effective pumping speed of the used pumps:

$\tau = \frac{V \, \textup{[Liter]}}{S \, \textup{[Liter/Sek]}}= \, [s]$

The following formula describes the increase of the leak rate signal:

$q_t = \left(1-e^{-\frac{t}{\tau}} \right)$

and the following formula describes the decrease of the signal:

$q_t = \left(e^{-\frac{t}{\tau}} \right)$