[sdiy] Where to buy ceramic caps

Michael E Caloroso mec.forumreader at gmail.com
Sat Dec 30 07:35:08 CET 2017


> Actually, my simulation suggests that even 5% tolerance caps would give
> suitably precise phase displacement.

Repeat after me:
do not place absolute faith in "simulations"
do not place absolute faith in "simulations"

I have read of many "simulations" suggesting precision parts in the
design phase that resulted in a circuit that never worked.

> I'm trying to achieve capacitors for which I can guarantee the value, for a
> 90-degree phase-displacement network, so I can avoid putting 12 multiturn
> trimmers on my PCB.

There are far easier designs out there for quadrature phase
displacement networks that don't rely on precision components.

You don't specify if your network is passive or active.

> I like ceramic caps because they are small

If you chose ceramic dielectric purely for their size then you're
doing it wrong.  ESPECIALLY if the network is passive.

> and I've already laid out the board for them.

You laid out a circuit board with total faith in a simulation without
actually proving the design?  BRILLIANT!

> I've found some of the caps I need on various sites, sometimes even for
> less
> than a dollar per.  I f*ck*n' HATE buying capacitors.  It's as if the
> makers
> don't actually want anyone to have them.  They are 10 times more expensive
> than they should be, when you can find them at all.  They're impossible to
> read, even with specs on.  It's bullshit, actually, and I don't know why
> the
> electronics world puts up with it.

Professional audio designers over the last forty years have played
with $$$ opamps and opted for alternate circuits that achieve the same
goals with cheaper opamps.  Like you, these same designers didn't want
to pay 10 times more for opamps.  So they sought out other designs
that would accomplish the same goal, or rolled their own.

Complaining about OEM pricing isn't going to solve any design problem.

MC


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