Why do we need an RC between GND and Chassis GND?

[sraja_23]

Why do we need an RC circuit, especially the capacitor between power
supply ground and the Chassis ground? will it not create an easy path for
the transients to go to the power supply GND?

 

[RF-OM]

All groundplanes must finally to be connected to the one common point. It is often called ground but actually there is no ground in RF and microwave engineering. We need to connect all return paths by the way when they are interact minimally. To achieve this we need to minimize common IR voltage drop in return paths. Practically it can be done with so called star-grounding when all grounplanes are connected to one common point by means of minimal impedance. Usually this common point is the power supply ground. Because there may be DC voltage difference between return paths and power supply common point such connection often done with capacitor. Resistors are used very rare, but sometimes it is necessary to adjust ground potentials for different groundplanes and in this case we may include small, but slightly different resistive elements such wires or small resistors and adjust them to equalize the potential on groundplanes. This is not easy process and it should be used only when you are positive that this is the right way. If it is done right there will be no way to transients to go into circuits because all potentials are equal and current cannot flow between equipotential points.