Shunt & snubber capcitors?

[madhu.b]

Hello,

what is difference between the shunt capcitor and snubber capacitor? What is use of it?

 

[Ogu Reginald]

First and foremost, any time you hear about shunt capacitor it means that the capacitor in question is connected in parallel to which ever circuit under reference.
While snubber capacitor (which can also be connected in parallel) are used as snubber to limit the effect of sudden changes in dV/dt and also to protect solid state components like the TRIAC from false triggering due to parasitic capacitance at their gate.
Shunt capacitors are found and used any where you see a capacitor connected in parallel. Sometimes instead of using a combination of RC in series as a snubber, a single shunt capacitor can be used as a snubber.

 

[madhu.b]

Hello Ogu Reginald,

I saw the shunt capacitor which is connected in parallel to the MOSFET. So, what is use of that?
And also your saying that the snubber capacitor also connected in parallel. So, how you can tell that is shunt or snubber capacitor??

You can see the capacitor & circuit diagram in the below link...

**broken link removed**

 

[SherpaDoug]

Shunt is how the capacitor is connected. Snubber is what the capacitor does.

A snubber is wired in shunt to what it is protecting, but it usually has a series resistance. It can either be a discrete resistor or it could be the inherent ESR of the capacitor.

 

[mtwieg]

The paper he linked to is about class E amps, so the shunt capacitor in question is not a snubber.

As was said above, a shunt capacitor means that it is directly in parallel with another part of the circuit. This is often seen in resonant circuits like the class E topology, or in resonant SMPS. It is not seen in hard-switched circuits, because it just causes more switching losses.

A snubber capacitor looks similar to a shunt capacitor on a schematic, but it is always combined with some other component(s) like resistors or diodes, so it's not connected directly in parallel with the switching devices. Its purpose is to reduce high frequency transients in hard switched circuits.

 

[Ogu Reginald]

The above replies has answered your questions rightly.