Simple Snubbers.

[greylourie]

Two examples are shown here, http://www.geotech1.com/forums/showt...400#post165400
And here, http://www.geotech1.com/forums/showthread.php?21435-gold-nugget-simulation&p=204736#post204736

I wanted to learn more about the means to calculate the required values of components and understand the interaction. I hit a brickwall. But for sure will come back to it all.

But I did find a link to a downloadable pdf that might be helpful : http://www.hagtech.com/pdf/snubber.pdf
It is entitled, "Calculating Optimum Snubbers" by Jim Hagerman.

And another called "SNUBBER DESIGN FOR NOISE REDUCTION IN SWITCHING CIRCUITS" by Sanjay Havanur : http://www.aosmd.com/res/application..._Reduction.pdf .

Hopefully of use to others.

[Altra]

I gathered some parts to experiment. The only references that I have seen
is the SD2000 and the QED. The SD uses a voltage comparator to control and the QED use a micro.
Most of the motor/relay snubbers use small value capacitors while the SD uses something like 200uF.
It seems the term snubber may have two meanings - one used as a damper and the other as a high voltage clamp.
The SD being a high voltage clamp at 180v?

This is the closest I have found for use with a PI detector

https://www.youtube.com/watch?v=2BIMFBAJ3_8

Here is a calculator for two types

http://www.daycounter.com/Calculator...lculator.phtml

[greylourie]

Hi Altra,

Thanks so much for those links. I will have to keep going back to them. Was trying to place the accent in the video, maybe Canadian ?

I instantly took a liking to the example circuit offered by crane in the second link in my above post. For use as a clamp. There seems to be many benefits from using one.

I read all posts I could find regarding the SD snubber, and have sort of grasped that it is feedback regulated. Its seems overly complicated for what it does. But what do I know ?
A cursory glance at the QED snubber with a mosfet switch in close proximity, and you'd be forgiven for thinking its an analogue of the SD one. A closer look, and it begins to resemble something similar to cranes example (but using resistance in parallel with the capacitor). Then there is a mosfet and resistors to earth, and depending on when the mosfet is on, there could be significant effect on damping. How that might/might not alter the clamping action, I have not grasped yet.

Anyway, thank for your reply and the handy links.

[Altra]

He sounds Canadian to me? His web page has a bunch of on-line simulations for different
circuits. Apparently you can modify them. I want to reproduce his simulation seen in the video.
http://falstad.com/circuit/e-index.html

[greylourie]

As an aside, I see he has a program called Ripple Tank. Although not free ($10) could be of great interest to Geotechers.