2pin and 4pin transistors

[2tonewarrior]

Hi, I´ve recently seen several Ge transistors with two pins and four pins. Where is the missing pin in the 2-pin ones? and what the 4 pin are for in the others?

The first looks like this one http://www.techzonics.com/2ad149-germanium-transistors.jpg and the second one is this http://www.radiomuseum.org/images/tubephoto_klein/af138_1.jpg


Thanks

[sgmezei]

From what I have read the 4th pin is for grounding the case. Mine work without grounding it if that helps.

[2tonewarrior]

From what I have read the 4th pin is for grounding the case. Mine work without grounding it if that helps.

Thanks!, good to know that. What about the 2-pin ones, anyone?

[mgwhit]

I read somewhere last night that the T0-3 format uses the case itself as the third pin!

[2tonewarrior]

I read somewhere last night that the T0-3 format uses the case itself as the third pin!

Thanks for the info, I figured it would be like, so the holes for the screws. Thanks you two!

Damn, every time i translate something with google translate it seems to me worst than if i would try to write it by myself.

[mgwhit]

http://www.interfacebus.com/semiconductor-transistor-packages-TO-3.html