Interfacing with Resistance Thermal Detectors.

N

Neil Fisk

Guest
I'm familiar with using a micrcontroller or stamp on doing this, it's not
very accurate because relies on the RC time constant.

Can anyone tell me how to achieve reading a resistance with op-amps instead,
from 5 to 140 ohms. There are IC's on the market that may help me here with
this problem, however I'm not quite sure what I'm looking for.

Thanks very much
Neil
 
Neil Fisk wrote:

I'm familiar with using a micrcontroller or stamp on doing this, it's not
very accurate because relies on the RC time constant.

Can anyone tell me how to achieve reading a resistance with op-amps instead,
from 5 to 140 ohms. There are IC's on the market that may help me here with
this problem, however I'm not quite sure what I'm looking for.
Click to expand...
How do you want to display the temperature?

Numerically on a digital display?

As a binary number in a microcomputer?

MikeM
 
mikem wrote:
Neil Fisk wrote:

I'm familiar with using a micrcontroller or stamp on doing this, it's not
very accurate because relies on the RC time constant.

Can anyone tell me how to achieve reading a resistance with op-amps
instead,
from 5 to 140 ohms. There are IC's on the market that may help me
here with
this problem, however I'm not quite sure what I'm looking for.


How do you want to display the temperature?

Numerically on a digital display?

As a binary number in a microcomputer?

MikeM
Click to expand...
And do you mean an NTC thermistor, or a platinum resistor?

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com
 
On Thu, 01 Apr 2004 21:08:47 GMT, the renowned "Neil Fisk"
<nfisk@telus.net> wrote:

I'm familiar with using a micrcontroller or stamp on doing this, it's not
very accurate because relies on the RC time constant.

Can anyone tell me how to achieve reading a resistance with op-amps instead,
from 5 to 140 ohms. There are IC's on the market that may help me here with
this problem, however I'm not quite sure what I'm looking for.

Thanks very much
Neil
Click to expand...
Two, three or four-wire?

Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
 
How do you want to display the temperature?

Numerically on a digital display? ........No

As a binary number in a microcomputer? .........Yes, but i will need more
than an A/D converter because of the limited range in ohms for the scale.

Thanks for Asking Mike
 
And do you mean an NTC thermistor, or a platinum resistor? No just a
variable carbon type which is used in the sensor. and it's low between 5 to
140 ohms, it's linear taper......if your wondering.


Thanks for Asking Tim...............
 
Spehro Pefhany> Two, three or four-wire?

3 Wire Sphehro

2 Red, and one White and red are common for both...........Ok
Neil
 
You must log in or register to reply here.

Welcome to EDABoard.com

Sponsor

Back
Top