[time-nuts] Re: measuring tiny devices

[Lux, Jim]

On 5/26/22 8:24 AM, Richard (Rick) Karlquist wrote:

The tweezers are really good *only* for single components - even if they 
come with test leads, that's for measuring something like a motor start 
capacitor.
I tried using tweezers (cheap ones to be sure) to measure a moderately 
complex assembly (trying to figure out stray C).  It was a gruesome failure.

>
> VNA's of any kind (no matter how small their size) don't work well on 
> components that are too far away from 50 ohms, at least if
> you make a simple minded s11 smith chart measurement.  There
> are complicated work-arounds for these measurements, but they
> require different configurations depending on what you are
> measuring, so there is no turn key or universal solution.


https://www.mwrf.com/technologies/test-measurement/article/21849791/copper-mountain-technologies-make-accurate-impedance-measurements-using-a-vna

describes the various approaches

>
> With the low price of available VNA's, anyone can afford to
> buy one, but that doesn't mean they know how to use it correctly.
>
Oh man, is that ever true.