Help identifying a part...

[zachomega]

I believe the part might be a Thermsistor, but I can't find specs for it.

The part is marked as follows:

"NTC
4,7
______
0149"

Oh, and what the heck can I do with these? 

-Zach Omega

[Izzy]

Looks like a ceramic cap to me.
Probably 4.7 pico Farad

[zachomega]

Unfortunately, it is definitely not a ceramic cap.  Thanks for the input though.

-Zach Omega

Looks like a ceramic cap to me.
Probably 4.7 pico Farad

[zachomega]

NTC = Negative Temperature Coefficient. 

The part's resistance goes down as temperature goes up.  Unfortunately, it is such a low resistance (in the ball park of 5 ohms average) that they seem pretty worthless for anything I can think of. 

Anyway, I have a whole box of these things.  <sarcasm>Yippee</sarcasm>

-Zach Omega

[markm]

Where the heck did ya come up with a BOX of THOSE? 

[analogguru]

These parts are used in switching power supplies on the primary side to reduce the switch-on current.

In the moment when you switch the SMPS on, the resistance is "high" and later gets lower.

analogguru

[John Lyons]

If only you had a box of NTK275s or Mullard Mustard caps, or better yet Western Electric 300B tubes...you could send the kids through college!

John

[zachomega]

I go to flea markets a lot and come up with boxes of all kinds of stuff.  It was just recently that I found these again.  I got excited when I saw them thinking they could be varistors...or even useful value thermsistors.  I don't think I had to pay for these so no harm. 

-Zach Omega

Where the heck did ya come up with a BOX of THOSE? 

[zachomega]

haha, yeah...The only good finds I've had have been a bunch of 3n201 Motorola transistors, which turned out to be pretty cool and kind of costly, and some telefunken 12ax7's.  I've actually got 4 sitting right next to me at the moment. 

I also find tons of panel meters, test equipment, books...and if I ever get around to sorting through them, I have tons of old IC's in various places used for various functions. 

And kids!?  haha...I hope not...I'm only 24. 

-Zach Omega

If only you had a box of NTK275s or Mullard Mustard caps, or better yet Western Electric 300B tubes...you could send the kids through college!

John

[Paul Perry (Frostwave)]

They are made from some kind of semiconductor material, so their
voltage/current curve is non-linear.
Whether it would be right for some kind of distortion unit, I do not know.
back in THE DAY, many ingenious circuits were designed around non-linear
resistors of various types.

[zachomega]

I read this interesting website on thermsistors.  They are actually made a lot like ceramic capacitors...hence the similar appearance.  Well this particular style anyway.  They come in a host of styles. 

-Zach Omega

They are made from some kind of semiconductor material, so their
voltage/current curve is non-linear.
Whether it would be right for some kind of distortion unit, I do not know.
back in THE DAY, many ingenious circuits were designed around non-linear
resistors of various types.