How I can identify negative sides and positive sides in PCB?

Question

I have remote control for car (rc toy) and I want to know how I determine positive side & negative side of pcb for each button (left , right, backword & forward) in remote

Answer 1

PC boards do have two sides, but they are not identified as pos and neg.

For a through hole PC board, usually the side with the silk screen (printing) on it is the side where the components are mounted, with the other side the one that is wave soldered.

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Answer 2

You need to get a DMM, a digital multimeter. Set it for dc voltage, put black lead on negative side of battery, then check the trace on each side of each button, with the button in normal position and when actuated. Watching the voltages on each lead will show you what it is doing, and help you to draw the schematic.