[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: MOV's

Original poster: Terry Fritz <teslalist@xxxxxxxxxxxxxxxxxxxxxxx>

Hi Paul,

At 02:43 PM 5/3/2005, you wrote:
Terry,
Thanks for the info. I went to that site and read all they have on TVS's. From what it says, a TVS is much more like an MOV than a zener and in fact they refer to a TVS as "a clamping device like an MOV." It says that a TVS will clamp a transient at the clamp voltage and divert it away from the device being protected. That was basically what I was asking in my original post. The schematic I have for driving an ignition coil with a Mosfet shows a 130V MOV across the DS of the Mosfet to "protect the Mosfet from transients." (note on the schematic) What I would like to know is if I can substitute one of these TVS's for the MOV in this application?? The TVS is rated 135 to 150 clamp voltage and the schematic calls for a 130V to 150V MOV.

TVSs have low power dissipation and only go to like 250V MOVs go to like 5000V or higher. A tvs is very fast but limited. MOVs are slower but can take super high hits.


Also, if a TVS conducts at its clamp voltage and stops conducting when the voltage drops below this level, isn't this basically what an MOV does? Could I substitute the TVS's for the MOV's in the Terry Filter?

Not enough power dissipation and may not "fail safe"... Right now, the MOVs in the filter will short out when they burn up, still protecting the NST ;-) You would also need a large number of TVSs due to the lower voltage for each.


Finally, I Googled the part number that Electronic Goldmine is using and the only reference I got was Electronic Goldmine!!! I looked at the part at Digikey and I don't see where it refers to this part from Elec Gold. How did you come up with the Digikey part and where do you find information like the Protection Notes you directed me to?

I have ordered thousands of TVSs from Digikey and have worked with them more than I like to remember at the hybrid die level...

If I could figure out how to locate this information for myself, I wouldn't have to annoy you so much!!!{:-) 

I knew what TVS stood for, and then google filled in the details easily.

I don't mind doing my own research at all but it seems that all I ever accomplish is to frustrate myself by finding zilch!

Google!!! But you have to know what phrase to look for.... Transorbs and TVS might be too general...


Thank you so much for your patience with me. I really do appreciate it more than I can say. You have been a really big help. Later. 

That is why we are all here ;-))

Cheers,

        Terry



Paul
Think Positive


----- Original Message -----
From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Tuesday, May 03, 2005 1:34 PM
Subject: Re: MOV's

> Original poster: Terry Fritz <teslalist@xxxxxxxxxxxxxxxxxxxxxxx>
>
> Hi,
>
> It is a transient voltage suppressor:
>
> http://www.protekdevices.com/appnotes/protektion%20note%202.pdf
>
> http://dkc3.digikey.com/PDF/T052/1140.pdf
>
> Not a MOV or Zener since it is made much differently.  But it works much
> like a Zener.
>
> Cheers,
>
>         Terry
>
> At 07:44 AM 5/3/2005, you wrote:
>>The Electronic Goldmine has a "diode" R2MLF-A1 that is described as an
>>"overvoltage protection diode" that is "designed to clamp at 135 -150V."
>>Reverse current is 1A. My question: Is this, or is it the same as, an MOV?
>>
>>I have a schematic for driving an ignition coil with a Mosfet that shows a
>>130V MOV across the DS of the Mosfet. Would this suffice?
>>
>>Paul
>>Think Positive
>>
>
>