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Equivalent to BF494 and BF495?


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Hi everyone, this is my first post on this forum.
First, I want to thank all the members on this forum, it's been very helpful to me!
I am looking for equivalent to BF494 or BF495 transistor...because I cannot find them where I am.
Does anyone know equivalent transistors? And what is the difference between the two? NPN and PNP?
Also, this could be very useful to me and many people,
how do you go about finding equivalent or close to equivalent transistor? You look at the maximum voltages for for the base collector and emitter, but what about the frequencies etc...can someone help on that? It would facilitate my researchs  greatly! :)
Thank you all very much!

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PNP is basically the opposite to NPN, the collector and base voltage is negative with respect to the emitter and the transistor turns on when the base voltage is 0.6V below the emitter.

The voltage is a maximum rating.
Ic is the maximum current rating.

The cut-off currents are basically the lowest current it will work down to.

Gain is the ratio of the collector current to base current which isn't well controlled and varies on the temperature and operating current. In this case the transistor is designed for low current operation so you need one with a similar gain at 1mA.

The frequency is the the frequency at which the gain drops to 1, as long as the replacement transistor has enough gain at the frequency used in the circuit, it doesn't matter, as a general rule higher is better.

Is this going to be a direct replacement on a PCB which has already been designed? If so you need one in the same package with the same pin-out which I think might be difficult because it's unusual - TO92 is normally CBE or EBC but this one is CEB.

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