A simple question

[redvette]

Hi gang

Here is a simple question. Why are some fans, case or CPU, three wired, red/black/yellow, where some are two wired red/black. If red and black are the power wires what is the yellow used for.? I was thinking for rotation direction but most fans you just turn them different directions for this.

Reason for asking is I cannot find a 2 wire fan, all I can find is 3 wired. The terminal on the board is for a 2 wire connector. What if I plugged it in, in such a way that the red and black got connected, and the yellow would be out in limbo, would that be my 12V.? Both of the fans are 12V, and same amp. The red and the black would be connected the same, red to the same terminal, etc.

Thanks........Gunny

[Panama Red]

The third wire, the yellow one, is simply a way to monitor the fan speed. If you use a 2 wire fan on a 3 wire connector, no fan speed detection will be possible.

[redvette]

Hi Panama

Thanks for the information. I appreciate it. I did not think of the fan speed.

Take care.....Gunny