So this morning I have placed an order for the current sensor amplifier max4172:

tunneldiode.blogspot.com/2020/12/max4172-taobao-order.html

... instead to make it yourself? In general, this is the better solution if your goal is the element under test...

I didn't catch you. I order the 8 pin SOP chip, so I need to use the SOP 8 top DIP 8 adapter board and hand solder the SOP chip to adapter. I forgot where I placed my SOP to DIP board, so I need to order some more, in case I could not find my old ones. I will also order ICL8038 through hole chips and DIY a fixed triangle sig gen, instead of using the bigger, hard to adjust module.

This is the adapter board for max4172:

This is the order for MCP4725:

tunneldiode.blogspot.com/2020/12/mcp4725-taobao-order.html

OK, I will look at them after my on-line meeting with my students where we are making "ideal diodes":) See en.wikibooks.org/wiki/Circuit_Idea/Group_64b and en.wikibooks.org/wiki/Circuit_Idea/Group_68b.

Ha, I watch your students doing the lab, and then more realized why I have an inferior complexity when talking to the real EE pros. I need to first introduced my background, when I studied the EE diploma in a sort of community college to be trained as a technician repairing radios in a Philips radio manufacturing factory, or American semiconductor testing plants. In short we learned more practical things, and not emphasizedon theories.

So, as I often said, after the EE diploma, I still don't know the meaning of opAmp virtual ground. I also don't know the deeper meaning of positive and negative feedback. Also we almost only used the locally made cheap equipment for repairing radios and the more expensive equipment was always locked in the cabinets. (1) So my first surprise was seeing your students can actually hands on, touching the high class equipment which I think are for industrial grade R&D labs.

So, as I often said, after the EE diploma, I still don't know the meaning of opAmp virtual ground. You should remember that not too long ago, I mentioned that I was very grateful for the two YouTube guys D Jones and the other name I forgot, explaining the meaning of virtual ground. I never dreamed that I can "investigate" the deep practical virtual ground.

(2) The other things is about dressing code. I must first mention that in those days in my city, a large proportion of people are refugees. So when I looked back, I should be dressed as a refugee in college. I still remember that I only had two cheapy coats and two jumpers which I wore for the whole winter. So I was so surprised to see your students/tutors dressed so smartly and fashionable in the lab.

Of course many years later our community collage upgraded a polytechnic and had business and even fashion design departments. Well, I am not complaining, because in those years only less than 3% of those eligible to enter a university, and perhaps 5% could go to a technical college. So fast forward decades, you should see why now I am so keen to make a (tunnel) diode oscillator, playing with opamps and ADC/DAC etc.

It is sort of a healing process, or repairing of my broken dream of not being able to go to America to study EE in a University. HongKong EE/ME industries did not go well after my graduation and technician years. Luckily I had other chances to study IT and software engineering and can still earn a decent living. Now the time has come to show off my software engineering knowledge and skills.

Just thinking aloud, sorry for all the typo errors. Almost bed time, see you tomorrow. Cheers.

Hi Fong, Again, I admire your gift for expressing yourself warmly and in such a human way. This is very rare on the web ... as if people there have lost their ability to communicate naturally ...

Regarding the emphasis on "theories"... Maybe the reason is in me simply because I was created that way - to look for the idea and after revealing it, to explain it to others. At the same time, I am a practitioner...

For example, yesterday I changed the timer of the stair lighting in the building where I live. For this purpose, I did some experiments with the buttons on the floors to find out if they are working. Also, I had to figure out the idea of ​​the timer to make sure it was damaged. Of course, these are simple but still practical skills that require some intuition and experience ... especially since it is not safe ...

Virtual ground... It is a simple but difficult to understand concept. I myself continue to look for an even simpler explanation of this phenomenon ... but in a more general form ...