Hi, I am a biologist and I do a lot of experiments on cellular electrophysiology. I keep my preamplifier and the biological subject inside a Faraday cage, and it works well. In some experiments I need to deliver a drug to the cell so I have to enter the cage briefly, with my hand only, and the delivering instrument. This introduces a low amplitude noise, visible in the recording, that lasts for as long as I am inside the cage. Why does this happen? How do you call this noise? I will really appreciate your answers! Amaranta.