What are the conditions when a ESD discharge occurs, in particular while handling components and assembled units. Can someone explain ESD discharge in the following cases - Let's say you are handling an IC, moving it around for soldering etc. What is the chance of the handler zapping the IC and under what conditions. There should be a potential difference between you and the IC. If you are just carrying the IC in your hand, where does the potential difference come from? Let's say you are handling an unpowered assembled unit (PCBA or a small product like mouse). Where does the potential difference come from for an ESD discharge to occur from your body to the product. Is a Metal object good enough for ESD discharge. There is discharge all the time when you touch a door knob or when you try to open the car door. Neither of these are connected to ground.