I'm pretty new to all this. Please forgive me if this is an obvious question.
I am working with an ESP8266 module. They generally have a max operating current draw of somewhere around 250 mA. I have noticed that under certain conditions it can seize up, and starts drawing current at an unusually high rate.
I am operating this off a steady 3.3v DC supply, so I was thinking of using a resistor to limit the current going into the module when this happens, but would like for someone to double check my math here.
At 3.3v a 10 ohm resistor should cap me well within my safe range at 330 mA, correct? Going further with the math, 330 mA at 3.3v would be just over a watt of power. So would I need a resistor rated for over a Watt?
Best Answer
You have a 3.3V dc supply and you want to limit current taken by using a 10 ohm resistor. If the normal operating current is 250 mA then the volt drop across the 10 ohm resistor will be 2.5 volts taking the 3V3 supply down to 0.8 volts across the device.
It won't work like this of course because I suspect the minimum operating voltage will be a shade under 3V BUT I couldn't find that info so you need to work that out.
My advice is get a 6V wall wart and a 3V3 LDO regulator and feed the regulator with but have the 10 ohm in series feeding the regulator.