Society of Robots - Robot Forum

Electronics => Electronics => Topic started by: Newguy123 on July 21, 2007, 08:15:34 PM

Title: Ceramic Capacitor
Post by: Newguy123 on July 21, 2007, 08:15:34 PM
I ordered the suggested Capacitors from Digikey (Cap .1uF 50v 20% Cer Axial), but the ones pictured in the $50 robot tutorial and the ones I got are totally different. Mine resemble small resistors. Has anyone else had this happen?
Title: Re: Ceramic Capacitor
Post by: KambeiX on July 22, 2007, 01:05:41 AM
do you have pictures?

inductors can resemble resistors but I haven't seen capacitors that look like them (but that doesn't mean they don't exist).

try to use it as a resitor in series with a led and another resistor, it shouldn't work because it will act as an open circuit.

(but of course the best would be measuring the capacitance/resistance with a good multi tester)
Title: Re: Ceramic Capacitor
Post by: Admin on July 22, 2007, 09:58:08 AM
Check the invoice and make sure the part numbers are the same.

There is the chance you ordered wrong, or they sent you the wrong parts.
Title: Re: Ceramic Capacitor
Post by: Ro-Bot-X on July 22, 2007, 02:12:10 PM
(Cap .1uF 50v 20% Cer Axial),?

The wrong word is Axial. That's why they look like resistors, they are built alike.

You should have ordered Radial. They are built upright.
Title: Re: Ceramic Capacitor
Post by: dunk on July 22, 2007, 05:23:05 PM
Quote
Quote
(Cap .1uF 50v 20% Cer Axial),?
The wrong word is Axial. That's why they look like resistors, they are built alike.

You should have ordered Radial. They are built upright.
in which case the difference is entirely cosmetic.
capacitors come in all shapes and sizes but it doesn't really affect how they work.
as long as the component you are looking at is a 1uF capacitor it should work fine.

dunk.
Title: Re: Ceramic Capacitor
Post by: HDL_CinC_Dragon on July 22, 2007, 11:12:43 PM
I got the same thing, the axial one.

How important is it actually that this capacitor actually be in the circuit at all?

Title: Re: Ceramic Capacitor
Post by: Newguy123 on July 22, 2007, 11:27:08 PM
Have a picture but not sure how to put it on here. To big to put it in a reply, limit is 600KB.
Title: Re: Ceramic Capacitor
Post by: Ro-Bot-X on July 23, 2007, 03:00:29 AM
Dunk is perfectly right, I forgot to mention that the functionality is the same no matter the aspect. 0.1uF capacitors are important to filter out the electrical noise induced by the motors or fast switching sensors. Mount them as closely as possible to all integrated circuits, especially the microcontroller.
Title: Re: Ceramic Capacitor
Post by: HDL_CinC_Dragon on July 23, 2007, 03:36:56 AM
ohhh ok so when the square wave is at its low point from the motors, it doesnt throw off the steady high point of power in the square wave that is required by the MCU?... Is that correct at all? lol
Title: Re: Ceramic Capacitor
Post by: jaabot on May 03, 2009, 03:07:47 PM
I had the same issue as the original poster, I ordered the suggested capacitor from Digi-Key and they sent the axial. I went to Radio Shack and found some 0.1 uF Ceramic-Disc Capacitors but they have 104m printed on them where the tutorial's pictures show 101. Does this matter? Which should I use, the ones from Digi-Key or Radio Shack. I have attached pictures. Thank you.
Title: Re: Ceramic Capacitor
Post by: SmAsH on May 03, 2009, 03:12:12 PM
you can trust either...
as long as radioshack have it right your fine...
Title: Re: Ceramic Capacitor
Post by: TrickyNekro on May 03, 2009, 04:30:49 PM
No... It should be 104 and it is 104....
This means 10 and 4 zeros aka 100000
And that is 100000pF or 100nF or 0.1uF....
Simple!!! :D
Title: Re: Ceramic Capacitor
Post by: jaabot on May 03, 2009, 05:06:50 PM
Thank you. That makes sense.

So does that mean that the picture on this page:

http://www.societyofrobots.com/step_by_step_robot_step3A.shtml (http://www.societyofrobots.com/step_by_step_robot_step3A.shtml)

(Near the bottom where it shows the capacitor labeled 101) is wrong?

Thanks.
Title: Re: Ceramic Capacitor
Post by: Razor Concepts on May 03, 2009, 05:26:03 PM
Capacitors can come in a variety of shapes and sizes. That picture is just one of many different shapes they can come in.
Title: Re: Ceramic Capacitor
Post by: jaabot on May 03, 2009, 05:30:24 PM
OK. Thanks very much.