Lecture 10: Bolometers - Leiden Observatory
Lecture 10: Bolometers - Leiden Observatory
Lecture 10: Bolometers - Leiden Observatory
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Detection of Light: <strong>Lecture</strong> <strong>10</strong><br />
Approximations for the temperature<br />
coefficient of resistance<br />
The electrical resistance for hopping can be described by:<br />
( /T )✏<br />
R = R0e<br />
...where ⇡ 1/2 and is a characteristic temperature ⇡ 4 <strong>10</strong>K<br />
The temperature coefficient of resistance is defined as:<br />
(T )= 1<br />
R<br />
dR<br />
dT =<br />
1<br />
R0e ( /T )1/2<br />
d<br />
dT<br />
(R0e ( /T )1/2<br />
) ⇡ 1<br />
2<br />
(T )= 1<br />
R<br />
Substituting the hopping resistance into the above equation we get:<br />
ALTERNATIVELY<br />
T> R = R0<br />
For one gets empirically that<br />
However, in both cases the point is that:<br />
✓ T<br />
T0<br />
= f(T )<br />
◆ A<br />
and so<br />
✓<br />
T 3<br />
dR<br />
dT<br />
◆ 1/2<br />
(T ) ⇡ A<br />
T<br />
...with A = 4
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