Batch of germaniums and need help identifying

[disabled_shredder]

I have a silver philco 2m1 dat 1762 with 225 vertical on it it is a slender package and also gold 2n1195 they have a gold tab and I think we or ge on the top. If anyone knows what they are please let me know also the philco are in an af package 5960-688-9008 af 33 (604)-40750 a 6/62. Hopefully the package info can help.

[LucifersTrip]

well, the 1195 is easy
http://transistor-spravochnik.ru/description/2n1195/593

maybe someone could help with the 225 if you had a picture. I have Philco 2n223's and sn224's like these

[disabled_shredder]

I only have my phone I'm not sure how to post a pic w it

[disabled_shredder]

Are the 2n1195s good? My friend gave me a cigar box of germaniums I got a handful of Air Force 2n404s and 404as also

[LucifersTrip]

good for what?

regardless, for the most part, the model number means very little. it mainly depends on the gain & leakage and it's different with each circuit topology.
404's usually have solid gains & leakages and are used by many...but you won't know until you measure em.

http://www.geofex.com/Article_Folders/ffselect.htm

[duck_arse]

those philcos would get by on looks alone, no matter how dud they were.

[disabled_shredder]

That is very true lucifers trip. I guess the reason that specific ones matter sort of to me is I've used many different types and I can almost swear that ic 140s always sound the best to me or at least are the most consistent. It's been a while since I've read over the biasing info is there a formula for the resistor values. I've always bought matched sets in the past. So I've had little need for the information on biasing. Also I've read the geo article on FF's plenty and didn't take away biasing info from it.

[disabled_shredder]

I don't know if anyone can view this but its worth a try I am having terrible trouble getting a pic up.

[disabled_shredder]

https://www.dropbox.com/sc/bla26za6hkz13jm/5f53N72k8z

[LucifersTrip]

oh, those bullet transistors.  I have to admit, I haven't had much luck with those (since usually very low hfe), but again, there are a bunch of different types, both germanium & silicon.

also, I've had the most Peak Atlas fails on those types. The Peak fails to identify ge or si many times.

The 225 is most likely not the model on yours, especially since the 225, according to this has > 3 lugs
http://transistor-spravochnik.ru/description/2n225/1863

Also, I have a Philco 2N504 (ge) in hand, with that exact casing and it has "260" written vertically. hfe ~ 15

I also have Philco 2N2182, 2N2183 (si) with that exact casing. They both also have "260". hfe ~ 10-15

[disabled_shredder]

Ok I've been holding off asking this for shame of a dumb question and I know there are no dumb questions but when I test the germaniums I set it to 9v readout and get x then throw the switch and get y I'm using the rig rg keen described and can you give an easier formula because 100e-6 times the number times 2472 doesn't make since. And once I get the true hfe how to I calculate the resistor values to bias the q2 to 4.5? I'm ok w math but I could never catch on to formulas. I'm horrible at algebra. I understand Steve Daniels formula great but I want better accuracy. Please help me get this figured out. I've built over 60 pedals 15 are original design and I think they sound great and not knowing how to match germaniums is really a downer

[LucifersTrip]

Ok I've been holding off asking this for shame of a dumb question and I know there are no dumb questions but when I test the germaniums I set it to 9v readout and get x then throw the switch and get y I'm using the rig rg keen described and can you give an easier formula because 100e-6 times the number times 2472 doesn't make since.

I don't know what you're doing.  You put Q in the socket and get x in volts. You flip the switch and get y in volts.  You subtract x from y, then multiply by 100 for gain.  The leakage is x/2472.

And once I get the true hfe how to I calculate the resistor values to bias the q2 to 4.5?

I'll leave that math up to someone who knows that stuff better. It's easier to use a trimpot
http://www.allaboutcircuits.com/vol_3/chpt_4/10.html

[Perrow]

 The leakage is x/2472.

I thought leakage was x times 100 

Reread the R.Gs article and can now see that you're right. Learn something each day 

[disabled_shredder]

Now that's a formula I can get down with. And yes trim pots do make since I just supposed there was some science to getting the bias resistor values just so.

[Perrow]

The formula is actually x / (2472 * 1000)A, as uA is sooooo bloody small. But the quick and dirty formula is x * 4 where x is the "gain". In R.Gs example the reading of 247mV means a gain of ~25, multiply with 4 and you get ~100uA 

[disabled_shredder]

Ok here is what I got can someone check my math I put a in the socket I got .06 with my dmm set to 9v read out that should be .02 with the formula for leakage the I get .70when I flipped the switch subtract the 2 x 100 and that's 70 hfe right?

[disabled_shredder]

On another I got 15mv as x and throw the switch I got 26mv. Could someone fill it in for me so I know what the final is and can go backwards w the formula to make sure I'm doing it right. I'm confusing myself so bad

[LucifersTrip]

The formula is actually x / (2472 * 1000)A, as uA is sooooo bloody small.

x/2472 in RG's example = .229/2472 = 9.3E-5 A = 93uA

But the quick and dirty formula is x * 4 where x is the "gain". In R.Gs example the reading of 247mV means a gain of ~25, multiply with 4 and you get ~100uA 

i don't think that's right

247mV = .247V
.247/2472 ~ 10E-5 which would be ~ 100uA

[LucifersTrip]

Ok here is what I got can someone check my math I put a in the socket I got .06 with my dmm set to 9v read out that should be .02 with the formula for leakage the I get .70when I flipped the switch subtract the 2 x 100 and that's 70 hfe right?

it's a run-on sentence, so difficult to understand, but it doesn't sound right.

put Q in socket, read .06
.06/2472 = 2.4E-5, leak ~ 24uA
flip switch, read .70
.70 - .06 = .64 hfe

[disabled_shredder]

Ok what does e-x mean when you typed that in. I only have a phone calculator. But basically that's a good q1 transistor w low leakage. I'm gonna get this sooner or later 2.4 e-5, leak ~24 ua?