1B05 Trash it or use it?

[mashaffer]

I came across four TO-3 devices in my parts bin today. The markings are quite worn but they all seem to say RCA 1B05 (NPN-Power Trans?). The funny thing is they have other numbers which do not match. It looks like CN 7737 and CN 7734.

Question 1... What do these other numbers mean?
Question 2... If these things check out on the diode tester are they worth trying to use them or should I just toss them?

mike

 

[Tube_Dude]

I came across four TO-3 devices in my parts bin today. The markings are quite worn but they all seem to say RCA 1B05 (NPN-Power Trans?). The funny thing is they have other numbers which do not match. It looks like CN 7737 and CN 7734.

Hi Mike...

Question 1... What do these other numbers mean?

77 year of manufacture 1977

37/ 34 the correspondent week .

Question 2... If these things check out on the diode tester are they worth trying to use them or should I just toss them?

Of curse you can use them. In his time , this transistors are made for "audio".

They are NPN.

Ratings:

Vce - 250 Volts

Pt - 150 W

fT - 5 Mhz

hFE - 15...75

Regards

 

[mashaffer]

Thank you

Thanks Jorge,

Do you happen to remember the Class A bias point for maximum linearity of Hfe (i.e. the flattest portion of the Ic v.s. Hfe curve)? I will be using them class A and want to bias for the lowest open loop distortion.

mike

 

[Tube_Dude]

Re: Thank you

Do you happen to remember the Class A bias point for maximum linearity of Hfe (i.e. the flattest portion of the Ic v.s. Hfe curve ?

Hi Mike

Around 350 mA...😉

 

[mashaffer]

Re: Re: Thank you

Thanks a bunch. You have been very helpful.

mike