considerations in replacing transistors???

[kebloks]

what parameters do I need consider in replacing transistors?

my idea... please tell me if i'm wrong

Vceo must be greater than or equal than the original.
Ic must be greater than or equal than the original
Power dissipation must be greater than or equal than the original.
Frequency range -- no idea >.< does it matter in DC operation?
Beta range - does it need to be exact?

any other parameters to be considered?

 

[ante1]

Hi kebloks,

Yes, that’s about it. But, it also depends on the circuit where you are going to replace the transistors.