[sdiy] Using non-linear passives

[Gordonjcp]

On Wed, Apr 05, 2017 at 03:04:19PM +0000, cheater00 cheater00 wrote:
> Hi guys,
> I've recently been reminded that ceramic caps (eg x5r) will only adhere to
> their rating up to 1V, and will then start losing capacitance as you go
> beyond. So effectively a DC bias could create a voltage controlled filter
> just like that, with no semiconductors. I wonder, has anyone tried this?

Not significantly.  I guess if you biased them up to a few kV you could get a couple of femtofarads of a swing out of it.

Bear in mind that varicap diodes actually have a practical method of operation where the gap between semiconductor layers varies with bias voltage, and need about 30V to get a couple of pF out of them.

-- 
Gordonjcp MM0YEQ