help on transistor... -_-

[roberto_manero]

gud day fellow enthusiasts...

i want to ask bout this transistor.. currently im a student studying IT so excuse me about my n00b-ness.. currently im constructing a temp. operated alarm/switch and im having a hard time finding this transistor..

2N3704 (they said its an old type of trans. and consider to find another replacement)

do any one know a replacement transistor for this... my circuit have 2 of these and runs on 9V

thanks for your help

 

[lord loh.]

http://www.datasheetcatalog.com/datasheets_pdf/2/N/3/7/2N3704.shtml

This seems to be an NPN transistor. The CB /BE /CE voltage ratings are similar to the ratings of the BC547/BC548. However the collector current of the BC548 is limited to 100mA while 2N3704 is capable of 500mA.

If current is not critical, you may use BC548.

Looks like you are using the transistor to amplify the reverse saturation current of some germanium diodes which are so often used in reverse bias as temperature sensors.

You can increase the values of a few resistors to limit the current of the load to 100mA and use BC548.

 

[Roff]

2N2222.

 

[lord loh.]

2N2222.

How can you say it so definitely? Is there is definite replacement table somewhere on the internet?

 

[samcheetah]

2N2222.

How can you say it so definitely? Is there is definite replacement table somewhere on the internet?

i think that didnt come from a replacement table but it came from experience :lol:

 

[Roff]

2N2222.

How can you say it so definitely? Is there is definite replacement table somewhere on the internet?

i think that didnt come from a replacement table but it came from experience :lol:

Thanks, Sam.
I looked at the datasheets on both transistors, and concluded that the ubiquitous 2N2222 (which I happen to be familiar with) should work in place of a 2N3704 in just about any application. I can't say the same for BC548.

 

[roberto_manero]

ah thanks guys currently im testing both since the other group has extra 2n2222's...