Multiple_Floating_DC_Power_Supplies

Thread Starter

odm4286

Joined Sep 20, 2009
265
Hey everyone, I'm learning so bare with me while I try to put my question into words.

Is there anything wrong with tying all the negatives of multiple dc power supplies together? So lets say I had a three separate floating(non earth referenced) power supplies, 3vdc, 12vdc, and 24vdc all powering different components in a circuit.

Would it be safe to make all the negatives of these power supplies common to each other?
 

Thread Starter

odm4286

Joined Sep 20, 2009
265
Ok thanks guys just to be safe heres an example. Ps1 24vdc to resistive load, resistive load to Collector of npn transistor, ps2 3vdc to base of transistor, emitter to ground, negative of both supplies to ground
 

Thread Starter

odm4286

Joined Sep 20, 2009
265
It won't work if you don't connect the grounds together.
That's exactly why i ask. The first time i played with transistors i had that problem so i ended up just using one 24vdc supply and regulators all over the place.

Good to know i can tie negatives together of different dc supplies to accomplish the same thing.

Yes sorry i forgot about the current limiting resistor to the base. That was just something i typed quick to get my idea across
 
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