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Availbale Products, Material- and Service suppliers => Wanted items => Topic started by: jadaro2600 on June 04, 2010, 12:31:00 AM

Title: The Bear of a Search
Post by: jadaro2600 on June 04, 2010, 12:31:00 AM
I'm looking for links to places where I can search through electrical components for the lowest cut-on voltage in a transistor.

Has there been any website created devoted to this type of searching - I'm trying to locate, in essence, a database of multiple manufacturers' information.
Title: Re: The Bear of a Search
Post by: CompuTutor on June 04, 2010, 01:02:17 AM

These might be of interest

http://www.greenoptimistic.com/2009/01/14/ald-mosfet-device-low-voltage-power-source/
http://www.freepatentsonline.com/6404268.html
http://www.physicsforums.com/showthread.php?t=292169

Darlington FET comes to mind too...



Title: Re: The Bear of a Search
Post by: jadaro2600 on June 04, 2010, 01:18:48 AM
Thank you, I'm looking for a transistor, NPN and PNP which have as low a voltage as possible for their cut-off, essentially, ..the point which the gate stops functioning and the transistor turns off.

I've been looking at Digikey; hopefully they'll send me a catalog.  the NTE catalog is huge, maybe I should go grab one of those, ...they actually have listings of these types of things.
Title: Re: The Bear of a Search
Post by: jadaro2600 on June 04, 2010, 01:41:58 AM
The germanium style transistors are rather pricey.  ...the NTE100 and NTE101 are exactly the type of performance I'm looking for in a small signal low power transistor, but the per-piece price is around 11 dollars, US.
Title: Re: The Bear of a Search
Post by: Pirate88179 on June 04, 2010, 03:05:52 AM
Jadaro:

As we have seen on the JT topic, the germanium transistors will work down to like .25 to .3 volts, maybe lower depending upon your circuit.

I have a few of these, hard to find but not all that expensive...IF you can find them.

Bill
Title: Re: The Bear of a Search
Post by: gyulasun on June 04, 2010, 08:52:14 AM
@jadaro

The correct term to search for is  ' low saturation transistor '

Zetex has been known as among the best, now they captured by Diodes Inc.  here is their link and enter the above key words:
http://www.diodes.com/search/index.php

You can find several other manufacturers with low saturation types:

http://www.sanyocomponentsdirect.com/Bipolar-Transistors/Bipolar-Transistors/Low-Saturation

http://www.onsemi.com/PowerSolutions/parametrics.do?id=808 

All these are bipolar Si transistors, with high Beta (hFE) (NOT Darlington), their base-emitter forward voltage is .7 - .8V.
Some of them seems to have better saturation voltage than a Germanium type, see here for instance, at Ic=100mA the sat voltage VCEsat=30mV,  this is the voltage drop between the collector-emitter:
http://www.onsemi.com/pub_link/Collateral/NSS1C201L.PDF

You may find them also by searching within bigger sellers pages like Future Electronics, Farnell, Digikey etc.

rgds,  Gyula
Title: Re: The Bear of a Search
Post by: jadaro2600 on June 04, 2010, 11:25:31 PM
Ah, thank you gyulasun, having the correct terminology search helps.

Hopefully I'll acquire some of these transistors and do some testing, but I think I can do without them for now.  These will be for third of fourth stage of development, or there abouts.

I purchased so many components about a half a year, I may have one or two and not know it.  I'm pretty sure I would have skipped buying a 10 or 12 dollar component.