What is generally considered to be the maximum allowable supply voltage variation?

The maximum allowable supply voltage variation is typically ±10% of the nominal voltage for most electronic devices and circuits. For sensitive equipment, this variation may be reduced to ±5% or even less. It's important to consult the specific device's datasheet for exact tolerances, as different components may have different voltage tolerances based on their design and application. Exceeding these limits can lead to malfunctions or damage.