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M1BYT > TECH 22.09.03 16:49l 60 Lines 2826 Bytes #999 (0) @ WW
BID : B71890M1BYT
Read: DB0FHN GUEST OE7FMI
Subj: Re: Pwer Supply Fan Mod
Path: DB0FHN<DB0RGB<DB0MRW<DB0SON<DB0ERF<DB0FBB<DB0GOS<DB0EEO<DB0RES<ON0AR<
GB7FCR
Sent: 030922/1444Z @:GB7FCR.#16.GBR.EU #:16109 [Blackpool] FBB-7.03a $:B71890M1
From: M1BYT@GB7FCR.#16.GBR.EU
To : TECH@WW
VK3EUB Opined with considerable skill:-
> I could not find any referance to an LM35 in any of my data books,
> i thought it may have been a mistake.
>
> Brian.
Odd, I found several referrences to it on the Internet.
<Quote>
The LM35 series are precision integrated-circuit temperature sensors,
whose output voltage is linearly proportional to the Celsius
(Centigrade) temperature. The LM35 thus has an advantage over linear
temperature sensors calibrated in ฐ Kelvin, as the user is not required
to subtract a large constant voltage from its output to obtain
convenient Centigrade scaling. The LM35 does not require any external
calibration or trimming to provide typical accuracies of ฑผฐC at room
temperature and ฑพฐC over a full -55 to +150ฐC temperature range. Low
cost is assured by trimming and calibration at the wafer level. The
LM35's low output impedance, linear output, and precise inherent
calibration make interfacing to readout or control circuitry especially
easy. It can be used with single power supplies, or with plus and minus
supplies. As it draws only 60 ตA from its supply, it has very low
self-heating, less than 0.1ฐC in still air. The LM35 is rated to operate
over a -55ฐ to +150ฐC temperature range, while the LM35C is rated for a
-40ฐ to +110ฐC range (-10ฐ with improved accuracy). The LM35 series is
available packaged in hermetic TO-46 transistor packages, while the
LM35C, LM35CA, and LM35D are also available in the plastic TO-92
transistor package. The LM35D is also available in an 8-lead surface
mount small outline package and a plastic TO-220 package.
<unquote>
It is basically a three pin precision temperature referrence IC, you
feed it + and -ve and the output voltage on the third pin is very
predictable against temperature. It also scales directly from volts
output to temperature. I used several in the design of a controller
sever years ago. Its high precision or scaleability is certainly not
needed for this fan contol circuit, a simple thermistor would of served
just as well.
ษอออออออออออออออออออออออออออออออออออออออออออออออออออออป
บ 73 from Harry, M1BYT @ GB7FCR.#16.GBR.EU บ
ฬอออออออออออออออออออออออออออออออออออออออออออออออออออออน
บ International Museums Weekend 19th+20th June 2004 บ
บ www.ukradioamateur.org/imw/index.html บ
ฬอออออออออออออออออออออออออออออออออออออออออออออออออออออน
บ The ARC's FL/RAE courses + Newcomers Intro to บ
บ to amateur radio:- http://www.ukradioamateur.org/ บ
ฬออออออออออออออออออออออออออออออออหออออออออออออออออออออน
บ QTH: Garforth, W. Yorks.. บ Timed 14:38 บ
บ harry.m1byt@tiscali.co.uk บ 22 Sep 2003 บ
ศออออออออออออออออออออออออออออออออสออออออออออออออออออออผ
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