RE: MOV's

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Jason Judd" <JJudd@xxxxxxxxxxxxxxxx>

Hi Paul,

I'd try the TVS, they don't have a finite life like MOVs. If it is doing
much clamping though you may find that its max power dissipation is
exceeded.

What is the voltage rating of your FET ? This would have bearing on the
TVS voltage rating I would choose.

Jason.

> -----Original Message-----
> From: Tesla list [mailto:tesla@xxxxxxxxxx]
> Sent: Thursday, 5 May 2005 3:16 AM
> To: tesla@xxxxxxxxxx
> Subject: Re: MOV's
>
> Original poster: "Paul B. Brodie" <pbbrodie@xxxxxxxxxxxxx>
>
> Well, no one has answered the question. Can I use a TVS
> instead of a MOV across the Mosfet driving my ignition coil?
> The MOV called for is rated 130 to 150V and the TVS I have is
> rated 135 to 150V clamping voltage. What thinkest thou?? :-)
>
> Paul
> Think Positive
>
> ----- Original Message -----
> From: "Tesla list" <<mailto:tesla@xxxxxxxxxx>tesla@xxxxxxxxxx>
> To: <<mailto:tesla@xxxxxxxxxx>tesla@xxxxxxxxxx>
> Sent: Wednesday, May 04, 2005 12:40 AM
> Subject: Re: MOV's
>
>  > Original poster: Shaun Epp <<mailto:scepp@xxxxxxx>scepp@xxxxxxx>
>  >
>  > Paul,
>  >
>  > I've read that TVS diodes conduct quicker that MOVs do,
> although I don't  > remember where I say it.
>  >
>  > For the Terry fiter, I doubt that you'll find 1800v TVS
> diodes.  I think  > you'll be stuck with MOV's in that application.
>  >
>  > Shaun
>  >
>  >
>  > ----- Original Message ----- From: "Tesla list"
> <<mailto:tesla@xxxxxxxxxx>tesla@xxxxxxxxxx>
>  > To: <<mailto:tesla@xxxxxxxxxx>tesla@xxxxxxxxxx>
>  > Sent: Tuesday, May 03, 2005 6:25 PM
>  > Subject: Re: MOV's
>  >
>  >
>  >>Original poster: "Paul B. Brodie"
> <<mailto:pbbrodie@xxxxxxxxxxxxx>pbbrodie@xxxxxxxxxxxxx>
>  >>
>  >>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.
>  >>
>  >>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?
>  >>
>  >>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? If I could  >>figure out how to locate this information
> for myself, I wouldn't have to  >>annoy you so much!!!{:-) 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!
>  >>
>  >>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.
>  >>Paul
>  >>Think Positive
>  >>
>  >>
>  >>----- Original Message -----
>  >>From: "Tesla list"
> <<<mailto:tesla@xxxxxxxxxx>tesla@xxxxxxxxxx>mailto:tesla@pupma
> n.com>tesla@xxxxxxxxxx>
>  >>To:
> <<<mailto:tesla@xxxxxxxxxx>tesla@xxxxxxxxxx>mailto:tesla@pupma
> n.com>tesla@xxxxxxxxxx>
>  >>Sent: Tuesday, May 03, 2005 1:34 PM
>  >>Subject: Re: MOV's
>  >>
>  >> > Original poster: Terry Fritz
>
> >><<<mailto:teslalist@xxxxxxxxxxxxxxxxxxxxxxx>teslalist@twfpow
> erelectronics.com>mailto:teslalist@xxxxxxxxxxxxxxxxxxxxxxx>tes
lalist@xxxxxxxxxxxxxxxxxxxxxxx>
>  >> >
>  >> > Hi,
>  >> >
>  >> > It is a transient voltage suppressor:
>  >> >
>  >> >
>
> >><<http://www.protekdevices.com/appnotes/protektion%20note%20> 
2.pdf>http://www.protekdevices.com/appnotes/protektion%20note%
> 202.pdf>http://www.protekdevices.com/appnotes/protektion%20not
> e%202.pdf>http://www.protekdevices.com/appnotes/protektion%20n
> ote%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
>  >> >>
>  >> >
>  >> >
>  >
>  >
>  >
>
>
>