[Retr0spectrum]

More commonly, voltage glitching does rely on removing capacitors etc., and extremely precise timing (nanosecond resolution, or below).

However, the fun part about this particular attack is that it does not require quite the same level of precision. The voltage is dropped incrementally until the CPU starts to make faulty calculations. It just so happens that AES is one of the most complex operations, and thus, the first to start faulting.