Why does the instrument take more time to settle or clear after taking larger samples?
The nature of the electro-chemical sensor used in the instrument is such that, as a sample of air is drawn into the sensor, the target species reacts and is ‘burned’ by the sensor to produce a voltage. The more ‘fuel’ there is to burn the higher the voltage. However, due to the fast reaction speeds and sensitivity of our sensor there tends to be a bottleneck of un-used fuel left in the sensor which has to be cleared before a fresh sample is taken. This is the clearing or settling process required to bring the sensor back to the equilibrium point. In general the sensor should recover from most concentrations in about five minutes – turning the instrument off for this duration helps as, when the instrument is off, special circuitry is enabled which ‘discharges’ the sensor as fast a possible. If, after five minutes, the sensor has not cleared then you may have a faulty instrument – see here for more tips.
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