I want to do this but....

[BenW]

where can i get a neat DPTP switch? I want it for a 12v/7v fan switch

DTDP is basically a switch with 3 possitions AFAIK, (ON/OFF/ON)

I really want a shop as in pc world instead of maplins etc because the switch is 50 and postage £2.50

[Taz]

Maplin shop? Here's the store finder:

http://www.maplin.co.uk/StoreLocator.aspx?doy=28m5

[BenW]

Ah, didnt realise they had shops!

Unfortunatly there doesnt seem to be one near me.

Just thinking about it, do i need a DPDT switch or can i have just a switch with 4 pins on the bottom instead of 6?

This is the page i've been looking at and it says DPDT switch, i see it has wires going to all 6 pins but if a dpdt switch is ON/OFF/ON can i not just have a ON/ON to switch between 12 and 7 volts?

Thanks
Ben

[Taz]

I think you will still need a DTDT switch (ON-ON version) to get 12V/7V to your fan. Not all DPDT swtiches are ON-OFF-ON (3 position, centre-off), you can get ON-ON DPDT switches as well and these would be better for you as you don't want the OFF position as this will turn off the power to your fan!

Also take a look at this thread for a bit more info:

http://forums.hexus.net/showthread.php?t=36266

[BenW]

Thanks, the reason i'm thinking about the switch is that i want to be able to switch to 7v in warm weather and 12v in hot weather/gaming

Might even do it at 5V and 12V

[SilentDeath]

www.rapidelectronics.co.uk are better than maplin, and have free postage unitll tuesday 8AM.

Have a look at here which has a lot of other ways to do it which give better results. I use the switched diodes method for low power things or for my waterpump I use a variable regulator (LM338T).

You would need a SPDT switch.

12v > fan > center of switch _ > ground (for 12v potential)
                             \ > 5v (for 7v potential)