hi guys, i cant find the transistor BF180, is there any transistor similar to BF180 that can do the same function ?

 

You might look for an NTE161; according to their cross reference they say is a replacement transistor.
http://www.nteinc.com/specs/100to199/pdf/nte161.pdf

 

thanx for reply,

is there any other one ? because this one also i cant find it

 

The BF 180 is (was) a T072 can NPN transistor used for high frequency and switching applications.

Max ratings

V = 30
I = 20MA
F = 675 Mhz

Unless you have very high current a

2N5179 or 2N5180

will substitute (they have only 10 Ma current rating), but are also to72 cans

Of course if the european universal standby, the BFY88 or BFY90 will also do here.

 

thanx for reply,

i am trying to build a 3rd overtone crystal oscillator circuit, u will find the circuit in the link below , third diagram

http://hem.passagen.se/communication/txo.html

they said below the diagram that the transistor is BF180 or similar , the question is, can i use 2N2222 instead ?

 

Yeah, your crystal range is 1 - 21 Mhz and the overtone range less than 100Mhz, well within the range of any modern small signal transistor.

So you have plenty of choice.

A 2N2222 should make it up there (Ft is 250 Mhz).
The 'a version 2N2222A will reach 350 Mhz so would be better.

Don't expect significant gain at these frequencies however.

 

thanx alot man ! i will use 2N2222