If I have a device that requests 6V input and I have an a/c adapter that outputs 9V, will the device draw only the 6V it needs or will it try to take all 9V and burn itself out? In this case the circuit is simply a light. It has the switch and the bulb with an optio of being powered by 4 AA batteries or 6V input. No amp requirement specified.
Watt’s it matter?