Dual rail supply question

[a45]

Hi,

Sorry if this is a stupid question

I'm trying to work out with where to place a power switch in my circuit, I'm using 2 9V batteries to get a dual rail supply (to power op-amps) and also a ground. All these 3 rails will be used in the circuit, I understand getting a dual rail supply can be achieved by placing 2 9V batteries in series getting a +9V, Ground and -9V. Where would I place the switch in order to stop all power going to the circuit? Am I right to put it on the +9V rail as am wondering if the middle ground rail will turn positive as the second battery is still running. I'm thinking its voltage should just go to the other batteries ground but want to check as a voltage regulators ground pin is connected to that rail and have already blown one up by feeding a positive voltage to it by accident.

thanks

 

[MikeMl]

You must use a double-pole switch, and break any two of the lines between battery pack and circuit.

 

[a45]

Do places sell these double-pole switches in toggle switch format as its required for a small project. Looking around double-pole switches seem to be sold as switches for houses. Ideally I'm looking to buy the switch from Maplin

thanks

 

[MikeMl]

DigiKey lists over 6000 switches in its data base.

A DPST toggle or rocker switch should do it.

 

[a45]

Found some thanks