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Topic: 10uF ceramic capacitors (Read 13973 times) previous topic - next topic

Re: 10uF ceramic capacitors

Reply #15
I don't think you can find lower esr then ceramic, problem with ceramic is that
 1. it is very unstable on temperature (value changes significantly)
 2. it is not linear trough frequencies

but esr is low as hell ..

so for audio it's not very good cap as it adds distorsions, but yes, for psu, they are great, but if you need nF in filtering you want to go with  styroflex or silver mica as they are linear and temperature resistant, no leakage ..

Re: 10uF ceramic capacitors

Reply #16
[quote author="jason"]
It sounds like you just want to start with a PC board of the existing design, and then maybe play around a bit with the firmware -- nothing wrong with this.
[/quote]

No, not really :D

I would like to start from his schematic as it is imo well made and then see if there's something we need to tweak (use mcu with more power etc etc). Then we design the pcb from scratch (I do not like his pcb at all !!). Then we make firmware. Anyhow, that's was what I was planning to do before I got me a good lcr meter.


[quote author="jason"]PGAs are easily implemented with a common op amp and a handful of resistors.  I have a simple example in my portable software-defined transceiver which I will post soon.  For finer resolution in gain control, you can implement a VGA (variable gain amplifier) with a common op amp and a FET uses as a variable resistor, driven by a DAC output (which can be calibrated to optimize precision).[/quote]

comparing price and the specification of the pga's from mchip and board space and cost for making the same thing with fet's and resistors, I really see no point in not using the device like MCP6S22 or MCP6S92, they cost something like $1 or less

Re: 10uF ceramic capacitors

Reply #17
That design is the only working design I found, so that's why I wanted to use that design as my starting point. I was actually more interested in having "working tool" then in process of making one :D so now when I have a working tool I can look at this project from different perspective (enjoy making it vs make it so that I can use it). I'm not that knowledgeable in what is/was available on the market (as those are super expensive devices out of my reach) and I was never good in finding schematics for those devices (scopes, tracers etc..) but if you have schematic for some great devices, bring them on :D, I'm more then willing to participate

Re: 10uF ceramic capacitors

Reply #18
Great excerpt ... There's lot of useful data in user guide for mine lcr ( http://www.tequipment.net/pdf/Hioki/3522-50E_02.pdf ) just they are scattered throughout the document... Still I believe there are soma important analog aspects of this project that are faaaaaaar beyond my knowledge so .. for me theory of operation here don't cut it.. there's just too much knowledge I lack here .. and not only "surface" stuff, I lack background too