Okay, I think I'm beginning to get it. I reread some articles about ESR with fresh eyes and what you wrote makes sense. Since I won't be ordering many of them, it looks like a safer bet to purchase a 10%, 1.5 Ohm ESR capacitor (Kemet PN: T495B105K035ATE1K5, Mouser PN: 80-T495B105K35ATE1K5). I figured the lower tolerance was good, but at the late hour I was researching everything, the ESR was messing me up.
Thank you for helping me understand more about these capacitors, I really appreciate it. - John N5JT ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐ On Friday, May 1, 2020 6:02 PM, Bob kb8tq <kb...@n1k.org> wrote: > Hi > > The only way to work out what you have is to find the data sheet on that > part. It should translate > between the manufacturer’s markings and the exact part number. That part > number will tell you as > much as can be known about the part. Some data sheets are a lot more complete > than others. > > There is no risk (other than financial) in putting a 5% part in place of a > 20%. There also is very little > risk in going for the low(er) ESR. > > If the part is just a bypass, even the value is a bit open. If the cap is in > a filter or on the output of a switcher, > things may be a bit tighter. > > Bob > > > On May 1, 2020, at 5:42 PM, John Bievenour j...@bvnhr.net wrote: > > I'm an amateur electronics hobbyist who's still a newbie (especially to > > SMD), so please forgive the basic question. > > I recently acquired a FE-5680A that was failing to lock on frequency (pin 3 > > never went low). It will power up, sweep up and down, and finally settle to > > fluctuate around 9.9999999 to 10.0000000. > > When I opened the case, I found that one of the capacitors had blown, which > > I believe might be the reason. Looking at the top of the board, with the > > DB9 on your left, the capacitor in question directly across from the right > > hand 2941 voltage regulator. It has 105 on the first row, 35 followed by a > > stylized K on the second row, and 333 on the last row. > > I'd like to attempt to replace the blown cap. After doing lots of searching > > and reading, I'm pretty sure this is a Kemet 35 VDC 1uF SMD Tantalum > > Capacitor (never knew these existed until yesterday). I've narrowed down > > the options on Mouser, but I can't figure out: > > > > 1. is my identification correct? > > 2. is it a T489, T491, T494, T495, T496, T498, or T499 (the band at the > > top makes me think it's a T498, T491, T494, T495, T498, or a T499) ? > > 3. is the tolerance 10% or 20% (I think it's 10%)? > > 4. what is the ESR (I have options from 1 Ohm to 83 mOhms)? > > 5. for future reference, how am I able to tell the tolerance, ESR, and > > series just by decoding the writing on it? > > > > Thank you very much in advance. > > > > - John > > > > time-nuts mailing list -- time-nuts@lists.febo.com > > To unsubscribe, go to > > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
