I'm preparing to make a IR repeater much like the one at Radiolocman.com. I plan on using 2n2222 or 2n3904 transistors in place of the BC549 and BC337. Is there any problem with me doing that? I'm also using a 4.8V power supply instead of 9V. Thanks for any help.

 

I would check the data sheets for each and see if the Hfe figures are similar. I wouldn't expect too much of a problem. They are all general purpose transistors.

 

Thank you very much for the help. After looking at the data sheets I think I'm going to use a 2N3904 in place of the BC337 and a 2N4401 in place of the BC549.