Okay you electronics people; I've got a queestion for you...

[Force Flow]

This is a circuit diagram for a baybus for controlling the speed of a case fan. I've been trying to trace the path of the electricity, but I'm unsure how the DPDT switch is configured. So, my question is, how are the connections on the switch grouped?

[bailey]

as it shows in the picture there is two sides on the switch the left side and the right side.

the left side is the power for a fan, with the center terminals of the switch being th comon terminal when the switch is in the up position then the top left terminal is connected to the center terminal thus applying 12 volts to the fan.

when the switch is in the down position then the bottom terminal will be connected to the center terminal thus applying 5 volts to the fan.

the right side of the switch is doing the same thing to change the voltage to the led, but only useing the 5 volt suply and a resistor for the lower voltages required for the led.

any other question

[bailey]

what a bummer, all that work and no points for it

[Force Flow]

Wait, so how would the terminals be grouped? Would it be in any of the three ways that are grouped in the attachment?

[bailey]

as I stated, the way it is drawn you have 3 terminals on the left side and 3 on the right sidethe two sides are two seperate switches

the center terminal is eather connecter to the top or the bottom

[mark70]

Looks to me as though the center terminals are common and switch to top or bottom terminals depending on switch position. if you have an ohm meter you can determine this easily. I think you will find no contenuity side to side only up or down- in other words your diagram on the left. The led will see 12 volts in either position and the fan will see 12 or 5 volts. Most all dpdt switches that I have seen work in this manner but an ohm meter is a necessary safety check-good luck Mark

[Force Flow]

Thanks guys. I think that answers my question.

[bailey]

like this

[Paul Victorey]

Yes, if it's DPDT it's as mentioned, although you should know that sometimes, the connections are opposite of how the switch is thrown. Eg:

Switch up connects BOTTOM left to center left and BOTTOM right to center right.

Switch down connects TOP left to center left and TOP right to center right.

It actually depends, I guess, on the kind of DPDT switch. If you get the "handle" type, where the "handle" slants up or down (like your light switch), it's as mentioned above. If you get the slider style switches, it's usually the other way around (e.g switch up connects top left and center left, top right and center right, etc.)

[Force Flow]

Ah! That's a much clearer explaination, Paul. Thanks!