Cap Polarity and Resistor Pack Polarity

[alpha_uma]

Is the polarity (or the lack of such) of a cap a function of its dielectric
composition? What are resistor packs made of, and why are there polarized?
Some enlightening URLs would be appreciated. Thanks
Al-U

 

[Dave VanHorn]

alpha_uma" <no_one@nonesuch.com> wrote in message
news:sPLWc.206859$J06.166157@pd7tw2no...> Is the polarity (or the lack of
such) of a cap a function of its dielectric composition?

Yes. Air and ceramic caps are not polarized (there are other types as well)
and electrolytics, tantalums, and Supercaps are polarized.

What are resistor packs made of, and why are there polarized?

They aren't. At least not in that sense.

--

KC6ETE Dave's Engineering Page, www.dvanhorn.org
Microcontroller Consultant, specializing in Atmel AVR

 

[Walter Harley]

"alpha_uma" <no_one@nonesuch.com> wrote in message
news:sPLWc.206859$J06.166157@pd7tw2no...

Is the polarity (or the lack of such) of a cap a function of its
dielectric
composition? What are resistor packs made of, and why are there polarized?
Some enlightening URLs would be appreciated. Thanks

Legg pointed me to some useful electrolytic info in another thread. Take a
look at the thread on electrolytic working voltage, in
sci.electronics.design, for his posting; there are tech notes on the
construction of electrolytics that explain why the polarization exists and
what the consequences of reversing it are. Basically it has to do with a
different thickness of dielectric on the cathode and anode plates of the
capacitor.

One URL from his posting:
http://www.evox-rifa.com/n_america/technotes_electrolytics.htm


Are resistor packs polarized? Never heard of such a thing. Of course,
depending on the arrangement of the resistors inside, the pins of the
package will have different functions. But I've never heard of there being
a "+" and "-".

As for what resistor packs are made of, it depends on what kind! Take a
look at some manufacturer web sites to get more info on this. Google for
"thick film" as a starting point, that's one sort of construction.

 

[Peter Bennett]

On Tue, 24 Aug 2004 18:30:48 GMT, "alpha_uma" <no_one@nonesuch.com>
wrote:

Is the polarity (or the lack of such) of a cap a function of its dielectric
composition?

Yes

What are resistor packs made of, and why are there polarized?

They are made of the same stuff that regular resistors are made of.

They are not polarized, but some resistor packs have internal
connections between the resistors, which will make the orientation you
insert them in a board important.

For example, you can get a 10 pin single in-line resistor pack with 5
individual resistors. One resistor will be connected between pins 1
and 2, the next between 3 and 4, etc - you can insert this type either
way around without affecting the circuit operation.

Another 10 pin SIP may have 9 resistors, with one end of each
connected together, and to pin 1 - inserting this one the wrong way
round will upset the circuit.

Some enlightening URLs would be appreciated. Thanks
Al-U

For some information on resistor packs, have a look at
http://www.bourns.com

--
Peter Bennett VE7CEI
email: peterbb4 (at) interchange.ubc.ca
GPS and NMEA info and programs: http://vancouver-webpages.com/peter/index.html
Newsgroup new user info: http://vancouver-webpages.com/nnq

 

[alpha_uma]

"Walter Harley" <walterh@cafewalterNOSPAM.com> wrote in message
news:cgg7ka$tus$0$216.39.172.65@theriver.com...

"alpha_uma" <no_one@nonesuch.com> wrote in message
news:sPLWc.206859$J06.166157@pd7tw2no...
Is the polarity (or the lack of such) of a cap a function of its
dielectric
composition? What are resistor packs made of, and why are there
polarized?
Some enlightening URLs would be appreciated. Thanks

Legg pointed me to some useful electrolytic info in another thread. Take
a
look at the thread on electrolytic working voltage, in
sci.electronics.design, for his posting; there are tech notes on the
construction of electrolytics that explain why the polarization exists and
what the consequences of reversing it are. Basically it has to do with a
different thickness of dielectric on the cathode and anode plates of the
capacitor.

One URL from his posting:
http://www.evox-rifa.com/n_america/technotes_electrolytics.htm


Are resistor packs polarized? Never heard of such a thing. Of course,
depending on the arrangement of the resistors inside, the pins of the
package will have different functions. But I've never heard of there
being
a "+" and "-".

As for what resistor packs are made of, it depends on what kind! Take a
look at some manufacturer web sites to get more info on this. Google for
"thick film" as a starting point, that's one sort of construction.

Thank you all for your explanations and reference links about "cap
polarity". The following link at evox-rifa.com is especially helpful to
further my layman's understanding of the internal constructions of an
electrolytic cap:

http://www.evox-rifa.com/n_america/lytic_voltage_limit.htm

Al-U

 

[alpha_uma]

...
For some information on resistor packs, have a look at
http://www.bourns.com

--
Peter Bennett VE7CEI

Thanks for an the link. Quite informative.
Al-U

 

[Dave VanHorn]

Rifa did excellent work there, and in their line of stepper controller
chips, which they later sold to Unitrode and a couple of other outfits.

--
KC6ETE Dave's Engineering Page, www.dvanhorn.org
Microcontroller Consultant, specializing in Atmel AVR