8x Pomona style Double banana plug - Converted to multimeter TEST accessories

[Kiriakos GR]

This is possibly my last DIY and multimeter calibration gear adventure for 2019, as we are almost a month away of New Year 2020. 

Within 2018~2019 even Pomona style Double banana plug did not escaped from be copied in China.
Naturally the economy Made in China version this is a 60V max product with generic 10A max specification.

In the baskets of China this is now promoted as Speaker Double banana plug.
 
Personally as consumer and as Blogger I am today 100% educated regarding secrets of  China regarding test accessories  manufacturing process , materials in use , and design.
Speaking of design .. I learned allot from my adventure relative with BNC to dual banana plugs.
BNC to dual stacking banana adapters (Buying tip)

Then I did invested at getting of two REAL Pomona female BNC Double banana plug, and yes the quality it is there.

This time I am interested to get the Pomona style Double banana plug (due it robust mechanical assembly design) and to create one KIT of TEST accessories for multimeter testing.
My first thoughts are install over the dual banana plug reference electronic components as for example:
a Diode and or special diodes, ceramic capacitor , electrolytic capacitor or special passive components. 

For now I am patiently awaiting products arrival in Greece, I am assuming no later than two weeks from today.
Then, by the plugs at hand I will start this project and detailed and quality pictures will follow.   

Until then, you might be interested reading a relative ITTSB Blog post  Best Dual Banana plug / shorting bar ( Handheld multimeter calibration ) ?

[Kiriakos GR]

This purchase become another usual adventure relative to poorly made goods of China. 

In the quantity of eight plugs the one came with a missing screw.
If such screws design was a usual one I would not loose my temper.

1) Entire screws design of all screws this is problematic, there was no thought so the screw to have a protruding contact point this be capable to hold small in diameter wire.

2) Second discovered product design issue this is the GND tab at the side of the plugs,  suddenly the tab become smaller and instead of GND there is RH text instead?

3) Third discovered product design issue this is the available length or depth of the female 4mm tube,  this is extremely small / shallow, this blocking a male banana from getting stacked at the back when full size wire inserted at the front of the plug.

4) Allowed wire diameter this is no more of 2mm wire core, and minimum wire diameter should be no less than 0.6 wire core.
In both cases stacking at male banana at the back this is from impossible to problematic only when smallest diameter of wire this is inserted.
It seems clearly that the cheater who made this product, he thought the possibility of short and cheap banana plugs to be able to stacked at the back. 
 


Lots of visual proofs for you 
   

[Kiriakos GR]

After the first cold shower which I had regarding these plugs ( QC quality and design ), I thought to perform a few other tests.
This time I will follow the scientific path exploring and measuring capacitance of such dual banana plug.

The known fact this is that we have two single stacking banana plugs in a distance of 19mm from its other.

I did use the LCR DE5000 in several frequency steps and the results they are quite interesting. 
At the lowest 100HZ step the plug measuring zero pF and the same at 120Hz, but at 1kHz and above things starts to change.
From 1kHz and above this plug starts acting as capacitor and appeared capacitance this approximately 0.6~0.8 pF.
I am saying approximately because LCR DE5000 this is not calibration standard and interesting enough even the FLK8846A it was able to sense and measure this tiny quantity of capacitance too.     
The test frequency of  FLK8846A at that lowest capacitance range is 160Hz triangle waveform (measured by GDS2102A).

In summary, at 1kHz an above the Dual banana plug becomes a capacitor of 1pF.