It turns out if you pull a mica capacitor out of a drawer and it says "470", there is a 50% chance that it is 470pF, and a 50% chance it is 47pF!
I was puzzling over why the second channel of the 5B/254M amp I just put together was oscillating when I biased it over 30mA.
Looked all over, could not see any differences.
I looked over the mica caps... they were the same (two said "100" and two said "470". Hmmm, but they were slightly different...
Turns out one said "470 +/-5%"and one said "470J" ("J" means 5% too). But the one that was labelled 470J turned out to be 47pF!
DOH!
Pete
I was puzzling over why the second channel of the 5B/254M amp I just put together was oscillating when I biased it over 30mA.
Looked all over, could not see any differences.
I looked over the mica caps... they were the same (two said "100" and two said "470". Hmmm, but they were slightly different...
Turns out one said "470 +/-5%"and one said "470J" ("J" means 5% too). But the one that was labelled 470J turned out to be 47pF!
DOH!
Pete