USB 12v switching

[gudenau]

I would like to switch 12v dc when the usb gets powered (while still providing some to the device with usb), how should I do this?

[Zener]

I think we need a little more details on what you want to do.

[gudenau]

What more do we need, like that the usb is going to the same device as the 12v dc?

[Zener]

Maybe a sketch or drawing would help. But there are many other great minds here who might know what you need.

[gudenau]

Oaky, I will get a scetch up as soon as I can, it should be up soonish, this is from my iPod and I am about to goto bed, then school, so...

[gudenau]

Got it.

[adafruit_support_mike]

How much current do you want to draw from the 12v line? If it's a little, you can use a transistor. If it's a lot, you'll want a relay.

[gudenau]

I am powering a old hard drive, from when 64gb was top of the line.

[adafruit_support_mike]

Power consumption for hard drives is usually around 10 Watts, so call it an amp of current.

You can probably use a mosfet like this one: http://www.adafruit.com/products/355

[gudenau]

Thank you, this has helped.