Mystery Diodes? Caps?

[Ben Lyman]

I'm starting a new topic to try and figure out what these are. I know at least one of you can tell just by looking at it so here's a pic. I think they say 102 Z 50v and have a symbol of some kind, maybe a U with a line under it?

EDIT:
My diode tester would not read it unless I attached a 9.21v battery, then the DMM read 827 in one direction and the screen went blank when I switched the probes around.

could the U symbol be a polarity indicator?

[Groovenut]

Is it possible they are 1nF 50V capacitors of some kind? They dont look like caps but the markings sure do.

[samhay]

50v Zener perhaps?

[Gus]

Like Groovenut posted

They look like caps to me 102 the value and 50 the voltage

google  etc. 50v 102z

[samhay]

> 50v Zener perhaps?
Actually, 102 suggests they might be 1mA current-limiting diodes.

Easy enough to tell, can you measure a DC voltage drop across them?

> My diode tester would not read it unless I attached a 9.21v battery, then the DMM read 827 in one direction and the screen went blank when I switched the probes around.
Just noticed this. That suggests diodes. Try 9V -> resistor -> diode -> ground. Vary the resistor (use a pot) and see what the voltage drop looks like.

[CodeMonk]

These may look like diodes, but they are caps.
Your pic isn't as close up, so I can't tell if they look the same.





I've got a few of them




I suspect that's what you have there as well.
And the "102 Z 50v" marking sounds like a cap.
I think mine has the "Z" on it as well, "224 Z" to be exact, which makes it 220nF and the Z if its the tolerance, Z is something ridiculous like +80/-20 or something odd like that. But the 100 or so I have tested are all around 1% or 2% within that, or closer.
I posted them on here a few years back.
Someone , I forget who, said they were probably ceramic caps.

Although plugging them into a diode tester and getting different responses with different polarities would seem to be a little odd for a cap, unless the cap is polarized.

Maybe plug another 1nF cap into your diode tester and see if it behaves the same?
Or measure them with a cap tester?

[anotherjim]

Not seen those before. Looks like someone put smd multilayer ceramic caps in axial packages.


One class of diode that often have no cathode "ring" marking is the DIAC or Trigger diode (terminals are Anode 1 & Anode 2). They have a "breakover voltage" rating, but those definitely appear to have caps inside.

[duck_arse]

I'm in your other thread suggesting thermistor. after scratching the webs, I'm still thinking thermistor.

caps in a bottle? who ever heard of such a thing?

[armdnrdy]

caps in a bottle? who ever heard of such a thing?

You've never heard of bottle caps?   

[Ben Lyman]

You've never heard of bottle caps?   

Ha, I almost said that too! Wouldn't it be cool to build pedals for sale and say in your description that you used rare NOS "Bottle Caps" for vintage tone.
Anyway, I think all who said "caps" nailed it. I feel like a rookie clown for trying to measure with a diode tester hooked up to a 9v battery, I was just putting the DMM leads on a battery in the diode test setting.
I tried rigging it with a pot and battery but I guess I didn't really know what I was doing there either. As I said before, my brain works in pictures, not words.
That's right, my thoughts are literally rhythmic color patterns and images, weird.

Anyway, can a fuzz pedal operate without an input cap? I figured probably not because if I jumper the input cap on my current breadboarded FF, it just  splutters and gates, putting out a barely audible guitar sound. So, next I tried a 1n9148 in place of the input cap, same splutter in one direction, reverse the diode and pretty much no guitar sound at all. Same with the next diode that I tried, a 1n4001.
So, pop the mystery piece in place and I get a loud perfect sounding distortion box, with super bright tone, like a DS-1 with the tone control cranked. Like a 1n input cap, I guess. 
My next question is: If this is a tiny little cap, is it useful in a guitar pedal at all?
I could go buy the other 1000 or so that they had, probably get them for $5.

Thanks to anyone that just read all that

[duck_arse]

boo! caps!

they should be used in ALL your builds needing 1nF caps, to get those glassy highs.

[Ben Lyman]

boo! caps!

they should be used in ALL your builds needing 1nF caps, to get those glassy highs.

Ha, glassy highs! why "boo"? Are caps not as good as diodes? Are these pretty much junk?
Z does appear to be the tolerance. +80% -20% couldn't be so bad on something this small, could it. I mean even +100% would mean a 1n might be a 2n, right? so who cares, lol

[armdnrdy]

why "boo"?

Halloween reflex? 

[duck_arse]

boo! caps. yay! thermistors.

we don't have halloweens here.

[Groovenut]

Yay! caps. Boo! thermistors.



I always thought Halloween was over rated anyway.

[Ben Lyman]

Is it unanimous? 1n 50v caps? would anything else work as a replacement for a FF input cap? I feel like my rookie test is not the proper way to find out but if you all say caps, then caps it is, I guess.

[anotherjim]

Could still be a Thermistor!
Set fire to it and see if it stops passing signal.

I've never tried that kind of ceramic cap in audio paths. Might be microphonic - tap it and see if it makes a noise over the audio.
Then again there is a theory that microphonic parts add extra secret mojo when playing at stupidly high volume and they add sound back.

[Ben Lyman]

Could still be a Thermistor!
Set fire to it and see if it stops passing signal.

I've never tried that kind of ceramic cap in audio paths. Might be microphonic - tap it and see if it makes a noise over the audio.
Then again there is a theory that microphonic parts add extra secret mojo when playing at stupidly high volume and they add sound back.

Okay Jim, so a thermistor would make a FF function with no input cap?
Later tonight I will hook it up to my DMM and heat it up to see what happens. Is holding a cigarette lighter under it for a few minutes sufficient to see if it's a thermistor?

[CodeMonk]

boo! caps!

they should be used in ALL your builds needing 1nF caps, to get those glassy highs.

Ha, glassy highs! why "boo"? Are caps not as good as diodes? Are these pretty much junk?
Z does appear to be the tolerance. +80% -20% couldn't be so bad on something this small, could it. I mean even +100% would mean a 1n might be a 2n, right? so who cares, lol

I use mine often (although I haven't built anything lately).
Easy to work with.
They don't take up much room.
They are a value used often in pedals, at least mine are, (224, 0.22uF, 220nf, etc), and I see that 1nf value used often.
And as I said, the 80+/-20 doesn't seem to mean a lot, at least with the ones I tested, they were all within 1% or 2% or less of their stated value.
I've got a shitload of them. And it seems you have access to many more, at a good price.
And they work fine in the audio path.

I suspect that maybe they were originally made to withstand harsh environments being encased in that glass.

You don't live anywhere in Southern California do you, and know about a certain place between Lankershim and San Fernando Blvd.?

[Ben Lyman]

Thanks codemonk, I have a good handful of these but maybe I'll go back for more.
And, no l live in Sacramento, which I think is probably considered NorCal.