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potentiometer

M

Michael A. Terrell

Jan 1, 1970
0
Does anyone know exactly what the resistance varies between with this
potentiometer?

http://www.radioshack.com/product/i...ters&fbc=1&kw=potentiometer&parentPage=search

How can you tell?

Thank you.


Its a 5k, +/- 20% 1/2 Watt linear pot. That means it varies from zero
ohms to 5K, or 5,000 ohms, +/- 20%, as measured from the center terminal
to either outside terminal.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida
 
D

Don Bowey

Jan 1, 1970
0
Does anyone know exactly what the resistance varies between with this
potentiometer?

The pot has three connections. The center one is the "wiper," which travels
(linearly in this case) along the resistance element (5000 Ohms, +- 20% in
this case).

Each of the outer connections is connected to an end of the resistance
element so the resistance between these two connections does not change.


So..... The resistance varies between the wiper and the outer connections.
http://www.radioshack.com/product/index.jsp?productId=2102789&cp=&fbn=Type/P
otentiometers&f=PAD%2FProduct+Type%2FPotentiometers&fbc=1&kw=potentiometer&par
entPage=search

How can you tell?

It's how pots are built.
Thank you.

Don
 
C

Chris

Jan 1, 1970
0
Does anyone know exactly what the resistance varies between with this
potentiometer?

http://www.radioshack.com/product/i...ters&fbc=1&kw=potentiometer&parentPage=search

How can you tell?

Thank you.

Hi, Mike. A couple of notes on Radio Shack potentionmeters in addition
to Mr. Terrell's good answer:

Radio Shack pots are frequently second quality parts which have been
brokered off. As such, you can expect one or more of several
limitations.

Linearity is a measure of the correspondence between degrees of pot
rotation and resistance. For instance, with a 5K pot with perfect
linearity, 10% rotation would show exactly 500 ohms delta R, 20%
rotation shows 1K, and so on. You may find these pots are sometimes
not very linear.

A more common, and more pressing problem with Radio Shack pots is their
residual resistance. An ideal pot would have zero resistance (zero
percent of full scale resistance) between the wiper and leg when the
wiper is turned all the way to that leg. These pots may have up to
several hundred ohms or several percent of full scale resistance
(frequently because of mechanical misalignment of the wiper with the
element).

Another typical problem is intermittent contact between the wiper and
the resistive element. Again, this is frequently due to mechanical
misalignment between the wiper mechanism and the resistive element.

Best check for all of these problems is to open the blister pack and
immediately connect an ohmmeter from the wiper to a pot leg, and very
slowly turn the wiper, observing the change in resistance. Be sure to
do two checks -- from the wiper to both legs. If the pot action is not
satisfactory (it depends on your application), take it back for a
refund.

Voice of experience on Radio Shack pots -- trust, but verify. It's
convenient to be able to get a repair component on a Sunday afternoon,
but these can be a headache.

Cheers
Chris
 
D

Dorian McIntire

Jan 1, 1970
0
Does anyone know exactly what the resistance varies between with this
potentiometer?

http://www.radioshack.com/product/i...ters&fbc=1&kw=potentiometer&parentPage=search

How can you tell?

Thank you.

Just to shed a little more light on the subject. Pots (potentiometers) come
with two main types of tapers (the resistive strip in the pot narrows with
some pots): linear (no taper) and log (logarithmic taper). There is also a
rare anti-log taper.

Linear pots are used typically in non-audio applications such as power
supply level controls or test equipment level controls.

Log pots are used mainly in audio equipment because of the non-linear
response of the human ear to sound levels.

The following link offers more than you need to know (at least for now)
about pots:

http://sound.westhost.com/pots.htm


Dorian
 
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