SparkFun Forums 

Where electronics enthusiasts find answers.

I just got a set of 4 channel bi-directional Logic Level Converters to shift 3.3v signal output of a NodeMCU to a variety of 5v devices I’ve used previously with an Arduino and Raspberry Pis (as the NodeMCU operates on 3.3v instead of the 5v of the Pi and Arduino). It is very sensitive to voltage so I thought I’d use a multi-meter to make sure the voltages coming out of the LLC are OK. I powered each side of the LLC with 3.3v and 5v as required, then applied 3.3v to one of the low level channels and measured the voltage in the matching high level side. But it seems every pin on both sides of the LLC are always set high. That is regardless of any voltage applied to any of the channels - *all* pins on the 3.3v side are 3.3v and all in the 5v side are 5v. I assumed it was a faulty unit so soldered up another one and got the same result. Is this a symptom of measuring these with a multi-meter? It just doesn’t seem right. I’d have thought channels are 0v unless powered by an input on the opposite side. Is this right or have I got a faulty batch of converters? Any guidance appreciated, as I’ve looked around fora and Google and can’t seem to find anyone who’s tested one of these LLCs in the way I’m trying to, so don’t know if what I’m seeing is to be expected or not.


Any help appreciated - I’ve looked around Google and can’t find anyone with the same problems I’m seeing.