Choice of resistors

[aman]

Does anybody have ideas as to when choosing resistors what should be
the criteria ? Right now for my design I am using all surface mount
chip resistors.
Axial resistors come in metal film, carbon film, wirewound and other
forms. Is there any rule as to when to use what ? I think like a
wirewound resistance is accurate but has high inductance. Is it right ?
Are there any other concerns to be taken into account for the choice of
resistors ?

 

[aman]

Also I was recommended by someone in my earlier design about 2 years
ago to use metal film resistors of 100ppm/C for my temperature sensing
circuitry. But now I want to change by design to surface mounts. If I
use chip resistors for the same circuit, are they as much temperature
stable as metal film of 100 ppm/C ?

 

[Larry Brasfield]

"aman" <aman.bindra@gmail.com> wrote in message
news:1110317634.335002.62100@l41g2000cwc.googlegroups.com...

Does anybody have ideas as to when choosing resistors what should be
the criteria ? Right now for my design I am using all surface mount
chip resistors.
Axial resistors come in metal film, carbon film, wirewound and other
forms. Is there any rule as to when to use what ? I think like a
wirewound resistance is accurate but has high inductance. Is it right ?

In some applications, the inductance of a wire-wound
resistor can matter. This is not common.

Are there any other concerns to be taken into account for the choice of
resistors ?

Here are some criteria I have had to use while
selecting resistors:
size
cost to procure
cost to mount
stability versus temperature
stability over time
accuracy
linearity
established reliability
frequency response
tendency to trap contaminants
vibration and shock resistance
equipment required to mount
steady state power rating
pulse power rating
Take your pick of what is relevant to your application.

--
--Larry Brasfield
email: donotspam_larry_brasfield@hotmail.com
Above views may belong only to me.

 

[Larry Brasfield]

"aman" <aman.bindra@gmail.com> wrote in message
news:1110317993.990837.312710@g14g2000cwa.googlegroups.com...

Also I was recommended by someone in my earlier design about 2 years
ago to use metal film resistors of 100ppm/C for my temperature sensing
circuitry. But now I want to change by design to surface mounts. If I
use chip resistors for the same circuit, are they as much temperature
stable as metal film of 100 ppm/C ?

The two attributes, "surface mount" and "metal film"
are orthogonal. While the most ubiquitous SMD
resistors are thick film, metal film parts are available.

--
--Larry Brasfield
email: donotspam_larry_brasfield@hotmail.com
Above views may belong only to me.

 

[aman]

My application of temperature sensing needs voltage gains to be fairly
accurate. My present design uses metal films. If I am changing it by
SMT isn't it better in general to use thin film and not thick film
resistors ?

 

[Larry Brasfield]

"aman" <aman.bindra@gmail.com> wrote in message news:1110318579.335425.116650@l41g2000cwc.googlegroups.com...

My application of temperature sensing needs voltage gains to be fairly
accurate. My present design uses metal films. If I am changing it by
SMT isn't it better in general to use thin film and not thick film
resistors ?

I would agree that is the safest course in the
absence of more information, and assuming
the other requirements are ordinary.

Your concern about inductance is likely to
be misplaced in a temperature sensing circuit.

--
--Larry Brasfield
email: donotspam_larry_brasfield@hotmail.com
Above views may belong only to me.

 

[aman]

Thanks Larry