i wondering about using different transistors then a circuit shows and what to look for in doing so, other then the obvious things.
in this case I'm looking to build a small fm radio and it calls for a BF494 (datasheet at bottom), but i do not have one of those in my parts pile, ive searched through about 25 different transistors i have on hand, checking their data sheets and i believe i have found two that will work.
the C3203 also the C3199, them seem like they can handle the job but i have been reading a bit but still dont understand. in this case i believe switching speed is the factor, and near as i can figure that has to do with the FT and FR, they are both around 120mhz same as the BF494
but i have a few transistors that are over 300mhz FR, would they work as well?
basically im asking two things here, one being, well these work for me in the circuit linked at the bottom, and the other is what do you look at to determine the switching speed and also other things you may consider in looking for a transistor not used in circuit diagram.
BF494 datasheet http://www.hestore.hu/files/BF494,495.pdf
C3203 datasheet http://pdf1.alldatasheet.com/datasheet-pdf/view/550190/KISEMICONDUCTOR/C3203.html
C3199 datasheet http://www.fgxdz.com/technicData/TO-92/C3199.pdf
Circuit in question and its "T1" http://3.bp.blogspot.com/-_etP0u4gS.../single+BF494+transistor+FM+radio+circuit.png
in this case I'm looking to build a small fm radio and it calls for a BF494 (datasheet at bottom), but i do not have one of those in my parts pile, ive searched through about 25 different transistors i have on hand, checking their data sheets and i believe i have found two that will work.
the C3203 also the C3199, them seem like they can handle the job but i have been reading a bit but still dont understand. in this case i believe switching speed is the factor, and near as i can figure that has to do with the FT and FR, they are both around 120mhz same as the BF494
but i have a few transistors that are over 300mhz FR, would they work as well?
basically im asking two things here, one being, well these work for me in the circuit linked at the bottom, and the other is what do you look at to determine the switching speed and also other things you may consider in looking for a transistor not used in circuit diagram.
BF494 datasheet http://www.hestore.hu/files/BF494,495.pdf
C3203 datasheet http://pdf1.alldatasheet.com/datasheet-pdf/view/550190/KISEMICONDUCTOR/C3203.html
C3199 datasheet http://www.fgxdz.com/technicData/TO-92/C3199.pdf
Circuit in question and its "T1" http://3.bp.blogspot.com/-_etP0u4gS.../single+BF494+transistor+FM+radio+circuit.png
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