Hi all, totally newbie here.

I’m trying to determine Amps using a SCT-013 (15A/1V, builtin “burden” resistor) using a NodeMCU (ESP 12-E ). Pin A0 is a 10-bit ADC convertor, input ranges from 0V to 3.3V.

I understand the concept of a Voltage divider (to limit a device to a max of 3.3V), but how can I get my CT’s output to get to 3.3V?

Using https://openenergymonitor.org/forum-archive/node/156.html and https://www.amazon.com/YHDC-SCT013-015-Current-Sensor-Transformer/dp/B01CU055IE#feature-bullets-btf (for #turns = 1800) I get that the builtin burden resistor is ~42.4Ohm (15*sqrt(2)=21.21A, secondary peak current = 21.21A/1800turns = 0.011A; burden = 0.5V/0.011A = 42.4Ohm).

Is there a simple way to “map” the 0-1V (from CT) to 0-3.3V (input range on A0)? I would rather not reduce my already poor 10bit resolution to use a “fraction” (i.e. 1/3.3 = 30%) of the 3.3V input.

Thanks.