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Static electricity is a danger to chips. The tiny transistors inside a chip use thin layers of glass-like silicon dioxide, just 250 nm thick, thinner than a virus. Static electricity can easily blow a hole through this layer, destroying the chip. Special diodes redirect static electricity safely.

The second danger facing a chip is "latchup": if the voltage on a pin is out of range, unwanted "parasitic" transistors can turn on, shorting power to ground and burning out the chip. Special "guard rings" around the I/O transistors block unwanted currents to prevent latchup.

The third danger facing a chip is "metastability". If a signal arrives at just the wrong time, the circuit can get stuck between 0 and 1 for a while before deciding on 0 or 1. This causes wrong results. It's like a ball wobbling on top of a hill, eventually rolling down one side or the other.