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  #1  
Old 03-12-2012, 10:49 PM
doug08 doug08 is offline
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Default Transistor equivalent for bf494 & bc548

I decided to use ksp2222a to replace the bc548, and mpsh10 for the bf494. Let me know if you also think this is OK. My circuit does not work , and the transistors are definitely good(tested them).

Thanks
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Old 03-12-2012, 11:56 PM
Audioguru Audioguru is offline
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You forgot to post your radio (?) circuit so we don't know its frequencies.
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Old 03-13-2012, 12:00 AM
doug08 doug08 is offline
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Default The circuit operates at 100 - 150 mhz.

It is a small transmitter. I have no way to put it online. I don't have a scanner. I found it in an old electronics book.

Thanks
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Old 03-13-2012, 01:13 AM
Audioguru Audioguru is offline
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OLD, I know. I worked with the BF494 in 1969. It was the RF amplifier in an FM car radio.
If you cause interference with FM radios or with airplane communications then you will be in for BIG trouble.
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Old 03-13-2012, 02:43 AM
doug08 doug08 is offline
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No worries with that stuff where I live. LOL. Back to my question, I looked at the spec sheets and it looks like the transistors I used should work. Do you agree or disagree. All I need to know. Thank You.
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Old 03-13-2012, 01:58 PM
doug08 doug08 is offline
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I did some hunting for info, and yes, I was correct, you can use the mpsh10(rotated 180 deg) in place of a bf494(like I did). The bc548 > ksp2222a is also fine.

http://electronics-diy.com/electroni...tic.php?id=812
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