[time-nuts] Re: measuring tiny devices

[Richard (Rick) Karlquist]

I have had good results with the LCR Research tweezers.
Search "LCR Research" on Amazon.  They work great on
anything you can pick up or probe with tweezers.

The general disclaimer on any kind of component measuring
device is:

Virtually all of them are ONLY suitable for measuring a
free-standing device, not one soldered into a PC board.
This is partly for technical reasons, but also for
marketing reasons.  The vast majority of money to be
made in this field is for high speed testers for component
manufacturers, not so much for R&D use.

The LCR tweezers at first glance would appear to buck the
trend by acting as a "free standing analyzer" due to its
tiny size.  This turns out to be not quite true.  A chip
capacitor soldered to a ground plane will measure 1/2
pF high, no matter what the value.  Trying to make an
embedded capacitance measurement of a capacitor in
a pi network is completely unsuccessful.

The one good thing about the tweezers is that they virtually
eliminate the "fixturing" problem with small components, that
plagues "big iron" out of Santa Rosa.  (Personal note:  I worked for
HP/Agilent/Keysight for 35 years, including designing network 
analyzers).  The tweezers are in no way a "nanoVNA" at all.
They don't work on that principle, which is good.

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.

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.

Rick N6RK



On 5/26/2022 5:58 AM, Lux, Jim via time-nuts wrote:
> On 5/25/22 3:16 PM, ed breya via time-nuts wrote:
>> Thanks Mike, for info on LCR alternatives. It's good to know of others 
>> out there, if needed. I have an HP4276A and HP4271A. The 4276A is the