do transistors need a reverse current protection??

[Adhith]

hello everyone..
I'm having a doubt regarding transistors. Suppose I'm trying to light up a 12v LED strip by switching a transistor (BJT) with a signal also, the same strip is powered by switching another transistor with a separate signal. So in this case if at an instinct only one transistor is switched on then, is there any possible chance of damaging the other transistor with the reverse current and should I avoid it by placing a diode??

[wraper]

Do you mean 2 transistors in parallel with each having it's base controlled separately?

[Adhith]

Do you mean 2 transistors in parallel with each having it's base controlled separately?

Yes that is what i meant. I think its an OR gate right??

[T3sl4co1l]

That is called wired-OR, yes.

To be perfectly correct, it's wired-OR when the inputs are positive logic and the output is negative logic; otherwise, it's wired-NOR (all positive logic) or wired-NAND (all negative logic).  These are just Boolean identities (read more about the subject, and reason it out -- all will become clear.)

There is no reverse current, because neither transistor is driven to negative voltage in the process.  If a transistor were voltage-output, it would; but it's not, so it doesn't.

Tim

[Adhith]

That is called wired-OR, yes.

To be perfectly correct, it's wired-OR when the inputs are positive logic and the output is negative logic; otherwise, it's wired-NOR (all positive logic) or wired-NAND (all negative logic).  These are just Boolean identities (read more about the subject, and reason it out -- all will become clear.)

There is no reverse current, because neither transistor is driven to negative voltage in the process.  If a transistor were voltage-output, it would; but it's not, so it doesn't.

Tim

Thank you very much T3sl4co1l for your suggestion. let me check on Boolean identities to get a more clear picture.