3 ms·
That is not true. Think about your hand and PCBs as two plates of highly charged capacitor (say couple kV). When the discharge happens it will hit a random com
by lmilcin 6y ago
That is not true.
Think about your hand and PCBs as two plates of highly charged capacitor (say couple kV). When the discharge happens it will hit a random component or trace. A lot will depend on what the component or trace is. If the trace is data path between some ICs it is likely going to destroy either of them because it has no other way to flow to equalize with the rest of PCB than through one of the chips at the end of datapath.
- userbinator 6y agoIf the trace is data path between some ICs it is likely going to destroy either of them because it has no other way to flow to equalize with the rest of PCB than through one of the chips at the end of datapath. For it to cause any damage it must be of high enough energy, which means voltage * current * time. Although the initial charge may be several kV, it quickly drops as it dissipates. Inputs have built-in ESD protection diodes which will serve to dampen the event greatly. The reality is, consumer ICs are not ultra-sensitive to ESD once mounted on a PCB --- and common assumptions may dictate that parts like CPUs are most sensitive, but if you consider the idle power consumption of a CPU ("leakage current"), and the fact that it operates at such a low voltage, you'll realise that the DC resistance is very low. One of the things you learn very near the beginning if you go into laptop repair is that the CPU power rails will look like they're shorted if the CPU is still in the circuit.