2n531 germanium transistors - any uses?

[stobiepole]

Hi. Just picked up 25 NOS 2n531 germanium transistors. The spec sheet goes like this:

Datasheet
Part Number = 2N531
Description = Complementary Monolithic Transistor Pair - BVCBO 15V
Number of Devices = 2
P(D) Max.(W) Power Dissipation = 100m
h(FE) Min. Static Current Gain = 25
f(T) Min. (Hz) Transition Freq = 3.5M
Semiconductor Material = Germanium
Package = TO-5

They're currently in the mail, so before they arrive I thought I'd ask if they'd fit any fuzz-related roles...

Chris

[stobiepole]

I should add that I think these are 5 pin, and I presume that transistor pair means there's two transistors in the one package...So I'm asking, will I be able to use one of these as if it was a pair of normal germanium transistors in a fuzz? Or as a pair of diodes?

[petemoore]

  Did you find a data sheet with the pinout?

[stobiepole]

Well, they're TO-5 packages, with 5 pins. I haven't found an actual datasheet for them yet, but one site lists a similar part as "AC127+128"...

So, does that mean there's a PNP and a NPN transistor in each package?

[stobiepole]

Okay, they've arrived. They are in metal tins with five legs - three in a row, with two beneath, like a small letter 'n'...

* * *
*    *

Presumably they contain a pair of transistors, one NPN and one PNP. Any ideas which leg is which?

[Paul Perry (Frostwave)]

You can work out the legs with clips to a multimeter with Hfe.
I expect the emitters are connected together; there are a number of exotic arrangements of PNP-NPN matched pairs that give class B push-pull audio output stages for transformerless transistor radios, and I think this is one of them. Might be worth swapping with a person who collects transistors for something more mainstream - should be worth a dozen ordinary Ge at least!