I have a small project that requires me to solder some wires to a PCB that converts 5 volts to 12 volts.
Here is a picture of the PCBs:
On the PCB to the left, there is no label of "negative or positive". How can I tell where to solder the red (positive) and black (negative) wires. Furthermore, on the PCB to the right, it says the output is "5-16V", even though when I bought it the description said 5V to 12. I am a bit confused.
What is the proper way to solder a red and black wire to the output "holes".
For instance: do I put the wire through the top of hole and solder from the bottom of PCB?
... or do I solder from the top?