Electronic – Determining if thestery PCB with barrel jack power connector is center positive or center negative

debuggingpcbpower

I lost the power adapter to the module used to drive a LIDAR sensor I have. I am planning to make a new adapter but one problem I am running into is that I can't figure out if the module's PCB sources positive power from the center of the barrel jack or from the outer of the barrel jack.

What are some strategies I can use to figure out which the PCB uses?

Edit: thanks for the help everyone but I took the easy way out and emailed the manufacturer. I thought this would be a total shot in the dark but figured it was worth a try before I break something. To my surprise they actually wrote back and told me what was what.

Best Answer

Study the circuit board and the components on it. Trace along the suspected positive and negative power tracks. Look for components that have identifiable positive and negative terminals.

Electrolytic capacitors have their negative terminals clearly marked. If you can find data sheets for any integrated circuits on the PCB, see which are the power and ground pins.

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