Re: Some grounding questions

Christian Walter wrote:

snip

ESD: This is where I am a bit unsure. What happens for example if I would touch a possibly sensitive pin with an external testing equipment charged up to <7.5kV. Because of the isolation I would not expect any problems because no current can flow. Except I would assume that there exists a capacitive connection to earth.

If an object holding a net electrical charge is brought into contact with (or even close proximity to) an uncharged object, charges will flow and redistribute themselves and breakdown may occur. It matters not how many layers of insulation or isolation exist between the earth and the object. This is the ESD case. Normally, we ensure that our test leads are ESD safe when working on sensitive components.

If one lead of a power supply or charged capacitor is brought into contact with a component, any current flow will be limited by the capacitance of the other lead to other components. This is not ESD but simple current flow and possibly voltage breakdown.

Does that help?

Chuck

.

Relevant Pages