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Questions about component choice

Posted by spaceorange12 
Questions about component choice
February 01, 2017 04:22PM
So I decided to take the first step in building a Sanguinololu and ordered all of the specialized parts off of Mouser last night. Today I went to RadioShack to find the components that I thought were more common. Unfortunately, they did not have many of the exact parts listed on the BOM.
First off, there were only 3 tantalum capacitors in the entire store, and none of them had a proper uF spec. So I bought some ceramic ones with the correct uF as backup. I am wondering if it would be appropriate to substitute the ceramics for the tantalums.
Second, there was only one type of MOSFET, so I bought two, again as backup. The manufacturer part # is L7812CV (Datasheet). As with the capacitors, I am hoping that these will be suitable replacements.
Hopefully someone with a bit more electronics knowledge will be able to guide me.

Edited 1 time(s). Last edit at 02/01/2017 05:32PM by spaceorange12.
Re: Questions about component choice
February 01, 2017 08:11PM
See [reprap.org] for mosfets to go for.
Re: Questions about component choice
February 02, 2017 06:21AM
Quote
spaceorange12
Second, there was only one type of MOSFET, so I bought two, again as backup. The manufacturer part # is L7812CV.

Watch out - this is not a MOSFET, but a voltage regulator!

You do need one voltage regulator tough for the Sanguinololu, but not for 12V as is the 7812, rather you need a 7805 for 5V.
Re: Questions about component choice
February 02, 2017 08:29AM
Thanks for the replies.
I went online and did some research after posting this, and confirmed what enif said about the RadioShack part not being a MOSFET. I went back to the Sanguinololu wiki page and found the exact part number, but it's been discontinued. Will any 60v, 30a MOSFET do?
I also went ahead and returned the ceramic capacitors. I figured that it wasn't worth it to experiment, especially since I will need to order the new MOSFETS online anyway.
Re: Questions about component choice
February 02, 2017 01:58PM
Quote
spaceorange12
Will any 60v, 30a MOSFET do?

Definitely no. Check out Dust's link. The MOSFET needs to have a low RDSon resistance (so it doesn't get too hot) and a gate-source saturation voltage ("Miller") below 5V (so it can be switch with a 5V logic signal).
Re: Questions about component choice
February 03, 2017 08:03AM
The original MOSFET recommended for the Sanguinololu has part number RFP30N06LE.
SparkFun has it stocked along with FQP30N06L, and claims that they are interchangable.
Would it be wise to order the FQP30N06L or is there a more appropriate option?
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