Looking for a good ESR meter

[johnsmith123]

Hi Guys,

Just looking for some advice on how I can measure an smd capacitor in circuit.
I have some boards that are having erratic problems.
I suspect that the crystal capacitor installed were incorrect values.

How can I measure these capacitors while in circuit?
Any advice would be greatly appreciated.

 

[Nigel Goodwin]

An ESR meter is for measuring ESR on larger electrolytic capacitors in, or out, of circuit - so no good for testing tiny capacitors in the low pF range.

There's no way to test such tiny values in-circuit, best thing to do is simply replace them with the correct values on acouple of boards, and see if that cures the issues - if it does, change all the rest.

 

[johnsmith123]

thanks for your response to my post.
The small capacitors are not labeled so its easy to misplace them.

is there a way to read the value of these 22pF capacitors when they are out of the circuit?

I have a well organized parts container for small smd boards containing all the smd components
(I only use 1206 packages because they are about as small as I can work with)
Sometimes the small capacitors get mixed up even though I separate the two components far away from each other.
I would rather not have ten different containers for the capacitors.

Here is another question,

Do you have any advice on a better (more organized) parts container for really small components?

Currently I use something like this:

The box does not seal really tight on the outer edge so the small 1206
component can enter another compartment if not kept horizontal.

Really what I am looking for is a smaller container to fit inside each of the compartments.
I am seeing lots of items on ebay but in my experience they are cheaply made and will fly open
causing the worst thing to happen!

A google search is not helping me.

Any advice is greatly appreciated.
Thanks

 

[Nigel Goodwin]

You might try one of the popular component tester kits from China, they read a huge variety of components, including ESR on later versions. The main problem with tiny capacitors is that the capacitance of your leads can swamp them.

As for SM parts, I leave them in the bandolier they come in, and only remove them one at a time as I use them - however, I avoid them where I can

 

[johnsmith123]

thanks for your response.
I am looking at one of these but I am not 100% certain that it won't keep the very tiny components separate from the next compartment.
Box-ALL

 

[Nigel Goodwin]

Worth a try, perhaps someone will come along who has one?.

 

[johnsmith123]

Yes I am hoping that someone will have some experience with this or similar products.

Like I mentioned above, I don't really want a dozen or so different containers for each part if I don't have to.

 

[dr pepper]

Depending on the circuit a crystal oscillator often works without the caps.
An ordinary multimeter that tests caps probablywouldnt go that low, a purpose made inductor / capacitor (lcr meter) might.
Or as nige says a cheap multi component tester, I use mine a fsir bit.

 

[gophert]

thanks for your response.
I am looking at one of these but I am not 100% certain that it won't keep the very tiny components separate from the next compartment.
Box-ALL

The box-all boxes are excellent for smd. I use them for 0805 size parts and have no problem. Just make sure to push them until the positive click closed before folding the box for storage -otherwise you have a mess. Wipe your hand across the box before you pick it up to feel that all are closed completely the one(s) that are not clicked closed will be obvious by touch. Not so obvious by looking.

 

[Pommie]

To get around the boxes not sealing well, use small ziplock bags in each compartment.

Mike.

 

[gophert]

To get around the boxes not sealing well, use small ziplock bags in each compartment.

Mike.

That is a super-inefficient waste of time. The All-Box boxes were perfectly designed for small parts and do not spill even 020 sized parts. I highly recommend themyou can fit 7 decades of E12 series parts (1 ohm to 8.2M ohm) plus 7 decades of E6 series capacitors (1 to 68pF/100 to 6.8nF/10nF to 680nF/1 to 68uF)

Plus 12 more compartments for your favorite and diodes, zeners, 2N7002 and more.

ALL IN A SINGLE BOX THAT IS SMALLER THAN A TEXTBOOK.

 

[unclejed613]

one method i use for measuring capacitance is to put the cap in series with a known inductance and feeding the series circuit with RF from an RF generator. at the resonant frequency the circuit acts like a short, so monitoring with a scope across the series circuit will show a definite dip in amplitude at the resonant frequency. now you have two known values, the inductance and the frequency. C = 1 / (4π2 f2 L) Capacitance [F] is how the capacitance is calculated, but it's much simpler to use the reactance chart:

since one property of resonance is that Xc=Xl, find the line for the known inductance, and where it intersects the resonant frequency, and then look at the capacitance scale for the result. this is one the most useful charts whether you work with audio or RF... i originally saw it in the ARRL handbook, and i keep a copy of it in a notebook along with other charts and miscellaneous information.

another way to measure the resonant frequency is having the cap and inductor in parallel and coupling a gate-dip meter to the inductor and noting the frequency at which the meter dips. this method would likely work better for SMD caps since you don't need to actually connect anything to the parallel resonant circuit. a gate-dip meter is an RF oscillator with a calibrated scale, and a meter that shows the amplitude of the oscillator output. the tank coil of the oscillator is externally mounted so it can be coupled to tuned circuits. at resonance, the parallel resonant circuit absorbs energy from the meter's coil and so the amplitude dips.

 

[dr pepper]

Does anyone use grid dippers anymore?
I have a couple.

 

[rjenkinsgb]

Does anyone use grid dippers anymore

The only thing mine has been used for, for the last 20+ years, is as a base for other boxes of junk to stand on in the attic...
It probably still works; it was a very nice unit for its age even when I got it, 5 - 400 MHz coverage.

edit - trypo correction..

 

[JimB]

OK, here is mine:

I built it around 1971 and it was very useful for many years.
It is far from perfect, some ranges don't work very well.
I notice in the schematic posted by rjenkinsgb that there are resistors in the coil units to configure the oscillator for the individual ranges.

Mine has not been used in a long time.
The last time I dragged a VHF receiver from 85MHz to 70MHz, changing all the RF, Mixer, and Local oscillator coils in the process, I used a little coupling loop connected between spectrum analyser and tracking generator.
I would hate to have to repeat the process using just a GDO.

JimB