Electronic – arduino – have to solder header pins


Coming to electronics as a hobbyist I'm not sure I understand why I have to solder header pins? On more than one occasion when dealing with Arduino / breadboard projects the circuit will not work until the header pins are soldered. Holding them in place will not solve this problem. Why? Low voltage? Need for persistent connection? Holding them in place doesn't work nearly as well as it looks like it should? Why?

Best Answer

Think about it mechanically - you have a straight row of pins and you insert them in slightly loose fitting holes (all in a line). Even if you hold them in place - can you be sure that one of the pins isn't fractionally bent in one direction different to the others. Think about this for a 3 pin header: -

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Clearly the pin in the middle isn't touching the inside of the yellow hole until you put unreasonable amount of pressure on the connector. Please, no complaints about the colours.