12V 180mA relay coil switching 240V 10A 10x voltage gain, 22x current gain. an a schmitt trigger-like transfer function. with a little negative feedback you could have a class-d amplifier with very poor bandwidth > Am I right? Who owes who a beer? And on that note, could a carbon
absolutely, Ive run old telephone mics and speakers off 12v and got sufficient gain for feedback-driven oscillations
wikipedia furnished this link:
probably, magnetic amplifiers, and spark gaps, do too.
bye.