Electronics > Projects, Designs, and Technical Stuff
Professional Prototyping Hardware Defined (Breadboard, Jumpers, low R stuff)
tggzzz:
--- Quote from: Mecanix on July 22, 2020, 10:33:47 pm ---
--- Quote from: tggzzz on July 22, 2020, 09:25:33 pm ---Not quite. The parasitic inductance of a 20cm lead is around 170nH. At a mere 10MHz that is 10j ohms, at 100MHz it is 100j ohms - in other words the inductance dwarfs a 1ohm resistance.
--- End quote ---
Let me see if I can rescue one of those abominable BB and jumpers out of yesterday's bin and plug back that LCR on one of those whatever/kit/plastic/thing. Let's see what sort of "x" (reactance?) this is pulling out. Might get better luck looking for Breadsword & Pumper wires I have a feeling. 20cm; was convinced the custom 5cm awg22 leads I crimped yesterday (to get me out of trouble) were already way too long...
--- End quote ---
The rule of thumb for a round wire is ~0.8nH/mm, often rounded up to 1nH/mm. Flat wires are lower, around 40%-50% the inductance of round wires.
So 5cm->50nH, ish. Whether that is a problem in a digital circuit depends on the transition time and (for ground pins) the number of outputs changing simultaneously, plus the load, of course.
julian1:
Breadboards are way too flaky when part numbers go up. But I really like solderable breadboards, with supply rails, and expected vertical traces that match ordinary breadboard layout.
Like these, https://www.adafruit.com/product/1609
Except I use cheaper Chinese no brand stuff - with rails down the centre as well.
They're flexible enough - if you make a mistake you just unsolder and resolder the part/s - the extra confidence from soldered joints is worth it. I try to make resuable modules, with lots of test points.
SMD stuff works fine too, using 2.54" breakouts.
tggzzz:
--- Quote from: julian1 on July 22, 2020, 11:09:11 pm ---Breadboards are way too flaky when part numbers go up. But I really like solderable breadboards, with supply rails, and expected vertical traces that match ordinary breadboard layout.
Like these, https://www.adafruit.com/product/1609
Except I use cheaper Chinese no brand stuff - with rails down the centre as well.
They're flexible enough - if you make a mistake you just unsolder and resolder the part/s - the extra confidence from soldered joints is worth it. I try to make resuable modules, with lots of test points.
SMD stuff works fine too, using 2.54" breakouts.
--- End quote ---
Yup. There are many commercial products in this area, each with relative advantages and disadvantages. Almost all are better than solderless breadboards.
There are a couple shown at the end of https://entertaininghacks.wordpress.com/2020/07/22/prototyping-circuits-easy-cheap-fast-reliable-techniques/ together with examples of other techniques for SMD and PTH components.
Mecanix:
--- Quote from: tggzzz on July 22, 2020, 11:07:48 pm ---The rule of thumb for a round wire is ~0.8nH/mm, often rounded up to 1nH/mm. Flat wires are lower, around 40%-50% the inductance of round wires.
So 5cm->50nH, ish. Whether that is a problem in a digital circuit depends on the transition time and (for ground pins) the number of outputs changing simultaneously, plus the load, of course.
--- End quote ---
Top class, and much appreciated Sir. I'll take your comment to the test and record its meaning in my notes. ty
joeqsmith:
A few other threads on breadboards that may be useful:
https://www.eevblog.com/forum/beginners/best-breadboard/
https://www.eevblog.com/forum/beginners/who-made-the-high-quality-breadboard/
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