Oh my darlington Clementine!

[Mark Hammer]

I'm trying to get a Scrambler working properly, and the pinouts on my trannies are driving me nuts.  Simply cannot get the sound I know ought to be there.  Normally I would corroborate the pinout with either a datasheet, or by measuring the hfe in my meter with different potential pinouts until I see a reading that is appropriate.  In the case of Darlington's, though, the hfe will be well outside the range of the meter whether I've nailed it or not.

As near as I can tell, there are several makers of 2N5306 transistors and the pinouts are not identical.  If the tranny has a big F on it, is that a Fairchild unit?

Is there a way to easily identify pinouts on a darlington using a meter?

[Seljer]

Hook up a voltage source with resistor of a couple of kiloohms in series with it to various combinations of pins (with the other pin going to ground) and measure the voltage.
In the case of an NPN darlington, when you get the base collector pins you should measure around 0.7volts, when you get the base emitter pins you should get 1.4 volts.

You could probably use the diode test function on the multimeter (mine is kind of finnicky above anything with a drop of more than one volt), in which case you look for the same thing, the base to emmitter drop is higher than the base to collector drop.

[R.G.]

Seljer's correct - one junction from base to collector, two junctions base to emitter.

[DavenPaget]

I'm trying to get a Scrambler working properly, and the pinouts on my trannies are driving me nuts.  Simply cannot get the sound I know ought to be there.  Normally I would corroborate the pinout with either a datasheet, or by measuring the hfe in my meter with different potential pinouts until I see a reading that is appropriate.  In the case of Darlington's, though, the hfe will be well outside the range of the meter whether I've nailed it or not.

As near as I can tell, there are several makers of 2N5306 transistors and the pinouts are not identical.  If the tranny has a big F on it, is that a Fairchild unit?

Is there a way to easily identify pinouts on a darlington using a meter?

http://www.advanced-tech.com/ic_logos/ic_logos.htm#F

[Mark Hammer]

Thanks, guys.  All very useful.  That page of logos will come in VERY handy.  Some of them are pretty obvious, where the semiconductor affords enough room to print out the whole name of the company.  Others not so much.

I gather that logos on SMD transistors are non-existent, although SMD chips still have some company-identifying info.

[DavenPaget]

Thanks, guys.  All very useful.  That page of logos will come in VERY handy.  Some of them are pretty obvious, where the semiconductor affords enough room to print out the whole name of the company.  Others not so much.

I gather that logos on SMD transistors are non-existent, although SMD chips still have some company-identifying info.

Some of them are oddly existant like TI .
i can see TI on a SOIC/TSSOP . 

[PRR]

Aside from Simon's excellent tip: foo on Darlingtons, get two simple (and known-pinout) transistors, make your own Darlington.

[Mark Hammer]

Aside from Simon's excellent tip: foo on Darlingtons, get two simple (and known-pinout) transistors, make your own Darlington.

That's certainly useful information for future reference, but at the moment I'm trying to tame a Tonepad board which will require me to identify a suitable unit and orientation to fit the board.

[candidate]

Getting the pinouts right took longer than building the pedal.

I could have sworn FuzzCentral had a layout, and that's what I used, because it was easier to modify.
http://fuzzcentral.ssguitar.com/scrambler.php
How many layouts exist?

[R.G.]

Getting the pinouts right took longer than building the pedal.
...
How many layouts exist?

If I had to guess, there's at least one per pinout of the part.

[LucifersTrip]

Is there a way to easily identify pinouts on a darlington using a meter?

no meter required...just slide em into a Bazz Fuss until it sounds right...

[dthurstan]

Hook up a voltage source with resistor of a couple of kiloohms in series with it to various combinations of pins (with the other pin going to ground) and measure the voltage.
In the case of an NPN darlington, when you get the base collector pins you should measure around 0.7volts, when you get the base emitter pins you should get 1.4 volts.

You could probably use the diode test function on the multimeter (mine is kind of finnicky above anything with a drop of more than one volt), in which case you look for the same thing, the base to emmitter drop is higher than the base to collector drop.

Am I right in thinking this will work with bipolar transistors also?

[Seljer]

Am I right in thinking this will work with bipolar transistors also?

Yes it will. Though the voltage drop will not have such a disparity. In general the voltage drop on the base to collecter is lower than base to emitter

Here is a page that descibres the method: http://www.allaboutcircuits.com/vol_3/chpt_4/3.html