using trannies as diodes?

[tungngruv]

I remember reading here about using transistors as diodes. After searching through this forum and the FAQ's, I still can't find the post. Can someone please point me in the right direction? Thanks in advance.

[RandomRedLetters]

the collector-base junction is a very low leakage diode. Test continuity because I forget which is the anode and which is the cathode. The emitter can be left unattached.

[aron]

Check this out:

http://www.diystompboxes.com/cnews/mods.html

[Sir H C]

Also there is what is called "diode connected transistors" where you tie the collector to the base.  In this format you get a very sharp knee.  Sometimes they call this a "super diode" (at least in old ARRL books).

[tungngruv]

Thanks very much everyone!!!!!! That's where I saw it Aron So once I connect the base + emitter, how do I know which end is the cathode? Once again, thanks in advance!

[Sir H C]

Collector and base is the "super transistor" and the collector is the positive side, emitter negative (for an NPN device).  With the base tied to the emitter you get a low leakage diode (IIRC) and then the base/emitter is the positive and the collector is the negative.

Either way, the base, for an NPN, is the positive terminal of the diode.

[DDD]

I've tried trannies as diodes in the diode clipper with couple of "diodes" in both directions. So there were 2 transistors - 1 pnp and 1 npn.
The sound was sandy comparatively to 1n4148 and I didn't like it.

[tungngruv]

Thanks again everyone!!!!!!! Sir H C, That's what I needed to know. Thanks!