If you can estimate speaker power, it probably is reasonable to use the ordinary power formula P = I²R for estimating the current the relay needs to handle. Typically, high-power speakers of a given kind are bigger than low-power speakers of the same kind. But as you can see from pictures of
40W speakers, some 10W speakers are smaller than some 5W speakers, and some are bigger than 40W speakers, so power estimation based on speaker size can be difficult.
Ovoz manbaiga (tyuner yoki pleer yoki biron bir kuchaytirgichga ulangan) kirishingiz bo'lsa, kuchaytirgichda ko'rsatilgan chiqish quvvatini topishingiz mumkin.
Har qanday holatda, kuch formula bo'yicha I2 terminiga qarab, rejalashtiradigan oqim oralig'i nisbatan kichik. Misol uchun, agar 5W 8 Ō dinamik, 5/8 = I² va I = 0.79 A bo'lsa, u holda 40W bo'lsa, u holda I = 2.24 A bo'ladi. Arduino bilan oddiy foydalanish uchun sotiladigan o'rni tizimlari.
Note 1: A relay's current rating ordinarily is derated significantly when the relay is used to switch DC or high-voltage AC. Audio is low-voltage AC and relay derating probably isn't needed. Note 2: The current a relay can safely switch in a live circuit may be much less than the unswitched current that closed contacts can carry. This might not be a problem with low-voltage audio. Note 3: Some commercial high-wattage audio distribution systems operate at higher voltages (see, eg, wikipedia's high-voltage audio distribution systems article, re 70.7 V etc systems); if you have one of those – as amplifier labeling might reveal – the example calculations shown above would need adapting.