can i use bd 139 instead of bc 547
BD139 is 80V, 1.5A, NPN TO-126, Minimum gain @ 5ma = 25......BC547 is 45V, 100ma, NPN TO-92, Minimum gain@ 2ma = 110 So a low order Yes as a general purpose application But not for a high FQ application and not a direct replacement. A
Select as Best AnswerUndo Best Answer
How do you tell the 'high FQ' (frequency?) part?
Well, the BC547 specifies a gain bandwidth fT product at 300 MHz and has numbers for input Cib & output Cob capacitance which leads me to think the transistor might be used in a radio or some other high frequency circuitry. The PDF for the BD139 never mentions the above parameters. You can read the PDFs for your self by clicking on the red pointers in this comment. A
What for ? It matters.