9v + (2xAAA) = ????

[thirdprize]

I have built two little kits I got from maplins.  One has a 9v battery and the other has 2xAAA batteries.  The 9v one is a sound generator and and the other drives a couple of little motors.

I would like to control them both with the same on/off switch.  Could i wire them both into the same switch or would the differing power sources cause problems?  Could i piggy back one off the others power supply? 

Any suggestions?

Shaun

[audioguru]

Since their supply voltages are very different, just use a two-pole switch that is two switches but with one toggle.

[windoze killa]

You could use a 3.3V regulator on the kit that runs off the 2 AAs. This way you could run them both from the 9V battery. If 3.3V is a bit much then you could also put a Schotky diode in series with the 3.3V supply.

[Staigen]

Hi

But the siliniode will use power

A silly question, what is a siliniode? Do you mean a silicone diode?

//Staigen

[windoze killa]

I think he means solenoid or more precise, a relay.

[Staigen]

Me too, but why dont he write that then, and why a big solenoid, a little relay
would be a better choice!

Staigen

[Staigen]

Hey, those last five words wasn't there before!


//Staigen

[Staigen]

And a relay will complicate things, and a linear regulator will waste power. But,
a swiched regulator will be just fine, but will complicate things too.

Staigen

[Staigen]

Hi helio905

This, i belive, you have to explain a little bit, and a little schematic would be nice too

Staigen

[audioguru]

You could use the same swich that you have. Connect the +'s
to your two circits and both -'s to the switch and then to the loads and
they should not affect each other.

If the switch has more than one contact then it is two switches in one like I said to use.

[Staigen]

Hi Audioguru

Hehe, a switch always have at least 2 contacts(connections), else it can not perform its task! ;D ;D
But i belive you mean poles(contacts) :) :D ;D

//Staigen

[thirdprize]

Wow, thanks for all the suggestions.  just to recap though ...
1)If i put a 3.3v regulator/relay before the 3Amp kit I can power them off the same source.  Whats the proper name for these things, just so i know what to get.
2)If i did the above thing then i could control them with the same switch, as they would both accept the same  current thing.  If not, then get a 2 pole switch that would control both circuits.
cheers.
Shaun