http://www.siongboon.com/projects/2006-06-19_switch/level_shifter.gif

Would this work as a high side switch using a NPN TIP120?

I've been using Infenion High Side switches, but they are hard to come by.

Or this using a PNP TIP120

http://www.opencircuits.com/images/6/60/Tran_hss.png

 

Both of these are NPN transistors, the TIP125/126/127 are the PNP complements to the TIP120/121/122 series, respectively.....

 

So i used a tip120(NPN) would those circuits work? Im pretty sure the second one wont work. My input to the base is only 5V. I believe the first should work. Ill be using 5V on the base and 12v on the collector.

 

The first circuit is a low side switch, not a high side switch.
The second circuit is an emitter-follower, not a switch. When the input to the NPN 2N3565 is +5.0V then the emitter is +4.3V. If you use an NPN darlington TIP120 then the emitter is only +3.7V. The high collector voltage does not affect the emitter voltage of an emitter follower.