Surprise find

[Monkeyboi]

Decided to give the workshop and storeroom a bit of a clean up.  Found a cardboard box with a paper bag in it.  Wondering what was inside before sending it to the wheelie bin I emptied the bag out onto the workbench to find hundreds of NOS silver mica capacitors.    No voltage rating on them, but I suspect they are probably 500v ?  Capacitance values - 56, 62, 68, 75, 91, 100, 110, 120, 130, 147, 160, 180, 200, 220, 240, 270, 300, 330, 360, 430, 470, 510, 560, 620, 680, 750, 820, 910 and 1000pF

 

There were some other 125v micas as well.  Mostly precision +/- 0.5% and unusual values like 802pF and 697pF.  Got no idea why I bought them or even when.  

 

So what does one do with all these silver mica capacitors?  Sort 'em, bag 'em and label 'em of course.  Just need a project to use them in.  Might build another phone stage.  There's always a use for ultra stable micas in the RIAA equalising and cartridge loading networks I guess.

 

Just a quick question that someone may know the answer to.  Some of the silver mica capacitors have a small dot of paint on them on the same side as the capacitance value is stamped.  The dots on each are either green, orange or white, whilst a few have no coloured dot at all.  I have googled extensively to find the answer but alas it still eludes me.    Not to be confused with the very old micas which used a coloured dot system to denote capacitance, voltage rating and tolerance.  Can anyone care to suggest what the significance of these dots may be?  I'm guessing tolerance ratings ????

 

 

Cheers,

Alan R.

 

 

[Zaphod Beeblebrox]

Nice find. No idea what the dots indicate. Perhaps they indicate closer matching? Whack 'em on a precision cap meter to find out. My first thought is for a Wein bridge as either an oscillator or a distortion analyser.