Pyroelectric infra-red sensors consist of a ceramic element, an alumina substrate and a circuit with field effect transistor (FET) and strong resistance, a window material.
To attain excellent sensitivity in a pyroelectric sensor, it is essential to make the pyroelectric element thin enough for a low-heat capacity. The engineers also must work out a specific sensor structure for little heat dissipation.
A pyroelectric infra-red sensor is using a conductive bonding agent to fix the pyroelectric element to the lead terminals of the stem. As a result, the clearance between the element and the alumina substrate holding the circuit remains constant, a construction that avoids heat dissipation. The element itself is between 50 and 100 um thick, to offer appropriate capacity and handling ease.
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Tasks for the text:
1. Find out the words: рассеяние, чувствительность.
2. Find out the sentence: Чтобы добиться отличной чувствительности пироэлектрического датчика, необходимо сделать пироэлектрический элемент достаточно тонким для низкой тепловой емкости.
3. Complete the sentence using these words: ceramic, alumina, infra-red, pyroelectric.
__ consist of __ element, __ substrate and a circuit with field effect transistor.
4. Explain the meaning of the technical abbreviation: FET.
5. What is wrong in the sentence?
The element itself is between 150 and 200 urn thick.
6. Make two sentences of one:
As a result, the clearance between the element and alumina substrate holding the circuit remains constant, a construction that avoids heat dissipation.
Translate the following:
1. The farther the grid is from the cathode, the more the plate current is. 2. The wider the distance between the grid wires, the more the plate current is. 3. The higher the temperature, the lower the conductivity of a metallic conductor. 4. The lower the temperature, the better the conductivity of a metallic conductor.