Thick film hybrid sensors : flow meter

Thick film hybrid sensors - flow meter

TeleControlli, leader in thick film technology, has recently realized hybrid air flow sensors which use the calorimetric principle. The operating principle works as follows:

the hybrid circuit main components are a thermal resistor (R heater) and a thermistor (NTC) made in thick film, as shown below.The thermal heater goes on electrically (it must raise to a temperature value higher than the surrounding medium); then the heater (R) is turned off and the sensor is “physically” cooled by the air flow which could be measured in this way (by the electronic control circuit).

The alteration of the electrical resistance (during the cooling) provides the data to determine the presence or the absence of the air flow and its speed too.

Note that the ceramic substrate (Alumina) serves as a better heat conductor than the air: the resistor subjected to the temperature (NTC) is heated indirectly by a separated heater (R) (which is printed on the Alumina like the NTC) through the ceramic substrate, avoiding in that way the worse heat conduction of the surrounding air.

Thanks to the hybrid technology, this kind of devices (although they are easy to make), they gain an high cost-effectiveness and reliability even compared to other technological solutions available today.

In add, they take advantage of the calorimetric operating principle and work without any moving parts.

You can also integrate other circuital functions (i.e. signal control circuit) on the same substrate.

TeleControlli technicians are at Your disposal to find the best custom solution adapted to Your needs.

 Datasheet

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