How do you measure a varying signal? Опции

[Herz]

Озадачил меня вдруг авторитетный источник.:

So perhaps we should disregard the polarity for power purposes? If, in the second case above, we removed the sign or polarity before taking the mean, then the “mean absolute” value would be 0.5 V just like the first case. But if we applied these two signals to the same resistor, it will get much warmer with the first signal than with the second, so the mean value of a varying voltage or current does not tell us enough about its heating effects.

У меня с английским так плохо или с азами ТОЭ? Диплом отнести вернуть?
То есть, я понимаю, что хотел сказать автор, но сказал он, по-моему, совсем не то.