# How to ON/OFF two fans with 3-state rocker switch?

I have a 3-state switch, It has 3 pins. It can have 3 state as you can see in the picture below. when it's off (i.e on O) the middle pin is not connected to anything! When it's on I, the middle pin is connected to I and when it's on II the middle pin is connected to II. Easy, Right?!

Now, I have two 5 volt DC fans and a 5 volt battery. I wanted to build a connection between these four elements that when the switch is on O, both fans are off. When it's on I, one fan is on and when it's on II, both fans will be on. I wanted to avoid using any other logical elements like gates or diodes, etc...

simulate this circuit – Schematic created using CircuitLab

All I want to have is just one switch, two DC fans and one DC battery. I couldn't figure it out how to do it, so I'm asking here! :)

If there is no way of doing it, is there a way to build it with minimum extra required elements?

• Looks like single pole double throw, with ON - OFF - ON state. You cannot actually do what you want, with both on at once in a certain state. you CAN have "left" and "right" Fans on or off though. But only one at a time. Commented Oct 14, 2014 at 10:59
• @KyranF, Thanks for your comment. so there is no way? :( what about adding some diodes to the circuit? Commented Oct 14, 2014 at 11:05
• Oh, I misread it, i thought you needed Fan A on during I, Fan B on during II, and both fans on with the O state. You may just connect the + of Fan A to I, and the + of BOTH fans to II. You do not need a diode. It will just be the two fans in parallel from the same output. No diodes needed. Commented Oct 14, 2014 at 11:21
• @KyranF, That's not right! when the + of both fans connect to II then the +s are connected! so when the switch is on I, both fans will be on!! Commented Oct 14, 2014 at 11:28
• Alternatively buy the equivalent dual pole version of the switch.
– user16324
Commented Oct 14, 2014 at 19:39