Hi gain NPN?

Frequently asked question on transistors: types, substitutions, how to test, use and misuse them.
Post Reply
User avatar
TV-Set
Breadboard Brother
Information
Posts: 137
Joined: 05 May 2012, 23:42
Completed builds: Silicon FF with tone control, Proco RAT, MXR Dist+, BMP, Phat Pig (custom 6 controls fuzz pedal)
Has thanked: 18 times
Been thanked: 2 times

Post by TV-Set »

High gain Si NPN, hFe possibly around or higher than 800.
Any suggestions??? thx

User avatar
Nocentelli
Tube Twister
Information
Posts: 2222
Joined: 09 Apr 2009, 07:06
Location: Leeds, UK
Has thanked: 1152 times
Been thanked: 954 times

Post by Nocentelli »

MPSA18?
modman wrote: Let's hope it's not a hit, because soldering up the same pedal everyday, is a sad life. It's that same ole devilish double bind again...

User avatar
TV-Set
Breadboard Brother
Information
Posts: 137
Joined: 05 May 2012, 23:42
Completed builds: Silicon FF with tone control, Proco RAT, MXR Dist+, BMP, Phat Pig (custom 6 controls fuzz pedal)
Has thanked: 18 times
Been thanked: 2 times

Post by TV-Set »

Nocentelli wrote:MPSA18?
MPSA13 is about the same?

User avatar
juanro
Cap Cooler
Information
Posts: 488
Joined: 01 Jun 2009, 17:07
Location: Argentina
Has thanked: 51 times
Been thanked: 117 times

Post by juanro »

Aren't those Darlingtons? If you don't have them you can rig your own with almost every NPN pair...

Regards,
Juanro


EDIT: MPSA13 is a darlington, MPSA18 is a general pourpose npn Hfe 500 - 1500. You can also try some 2N5089 Hfe 400-1200.
La única verdad es la realidad.

User avatar
TV-Set
Breadboard Brother
Information
Posts: 137
Joined: 05 May 2012, 23:42
Completed builds: Silicon FF with tone control, Proco RAT, MXR Dist+, BMP, Phat Pig (custom 6 controls fuzz pedal)
Has thanked: 18 times
Been thanked: 2 times

Post by TV-Set »

juanro wrote:Aren't those Darlingtons? If you don't have them you can rig your own with almost every NPN pair...

Regards,
Juanro


EDIT: MPSA13 is a darlington, MPSA18 is a general pourpose npn Hfe 500 - 1500. You can also try some 2N5089 Hfe 400-1200.
Rig em, that's what I'm doing right now. Is there some king of formula to calculate the hFe for such a Darlington? I used a pair of NPNs with very low gain (about 40 each) and measuring the resulting darlington with my dmm I read something over 1000 and then it sais the number's too damn large :mrgreen:

EDIT: ok, think I found it http://en.wikipedia.org/wiki/Darlington_transistor :thumbsup

User avatar
Seiche
Old Solderhand
Information
Posts: 2526
Joined: 01 Nov 2010, 00:16
Location: Germany
Has thanked: 231 times
Been thanked: 189 times

Post by Seiche »

just multiply the gains. so 40x40=1600 :wink:

User avatar
bhill
Solder Soldier
Information
Posts: 153
Joined: 03 Oct 2010, 02:18
Has thanked: 11 times
Been thanked: 5 times

Post by bhill »

2n5089 has hfe from 400-1200. should be fairly easy to find one in the proper range. And they are low noise.

Post Reply