Because it should not be detecting a capacitor when there is no capacitor.
Yep... Too bad they are imaginary.
What happens if you also put a 21nF cap in parallel with those coils (the one you calibrated with)?
Also in case of the 22uH inductor when it display "40nH if 21.3nF" what does the 40nH means?
What is the significance of knowing the resonant frequency with some arbitrary capacitance, who cares? And who cares what is the Q of that resonant circuit? Both of these parameters are totally meaningless.
To facilitate the measurements with this method I modified my super simple SMD test pads adapter to fit the 20nF capacitor.
Now I'm curious to see how the m-firmware will behave since it doesn't support this methos.
OK, if I put the 22uH inductor in parallel with my calibration capacitor then I get the correct (~22uH) inductance displayed. I still don't understand why only the AY-AT tester displays this "xxuH if xxuF" and requires this resonance configuration with the calibration capacitor. Also in case of the 22uH inductor when it display "40nH if 21.3nF" what does the 40nH means?
Another problem, when it displays the inductance correctly like in my example with the 47uH, on the 2nd line it displays some resonant frequency. In this case it displays 3618kHz, what is the significance of this resonant frequency? 47uH with 21nF (my calibration capacitor) DOESN'T resonates at 3618kHz, it resonates @ ~159KHz, so what is this 3618kHz frequency?
Any inductor will resonate with any capacitor at some frequency. What is the significance of knowing the resonant frequency with some arbitrary capacitance, who cares? And who cares what is the Q of that resonant circuit? Both of these parameters are totally meaningless.
The unit turns on (red LED, backlight on display etc.) but the screen appears blank (although lit up). I've read that it could be the contrast setting but I'm not sure how to adjust it blind. I believe you turn it on with a 2 second press to enter menu mode and then keep clicking to move through the different menu items. Can someone tell me how many times to press to get to the contrast setting? Any help would be greatly appreciated.
The unit turns on (red LED, backlight on display etc.) but the screen appears blank (although lit up). I've read that it could be the contrast setting but I'm not sure how to adjust it blind. I believe you turn it on with a 2 second press to enter menu mode and then keep clicking to move through the different menu items. Can someone tell me how many times to press to get to the contrast setting? Any help would be greatly appreciated.
You should carefully check everything, connections, resistor values, transistors etc. There is no trimpot to adjust the contrast on this version. Make sure the voltages are correct and the microcontroller is connected the right way. If everything is assembled correctly it should work. The contrast can only be changed by software and or compiling the firmware.
The only thing I found suspicious was the TL431 showing a dead short between pin 1 and 3, but I'm a newb so I'm not sure if this is expected behavior. Can someone help me determine if that indicates a problem?
The only thing I found suspicious was the TL431 showing a dead short between pin 1 and 3, but I'm a newb so I'm not sure if this is expected behavior. Can someone help me determine if that indicates a problem?
These two pins are supposed to be shorted, that is how you get 2.5v output, see schematic.
So I received mine from Amazon (link: https://www.amazon.com/gp/product/B06WW6QNFZ/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1) yesterday and soldered it up.
The unit turns on (red LED, backlight on display etc.) but the screen appears blank (although lit up). I've read that it could be the contrast setting but I'm not sure how to adjust it blind. I believe you turn it on with a 2 second press to enter menu mode and then keep clicking to move through the different menu items. Can someone tell me how many times to press to get to the contrast setting? Any help would be greatly appreciated.
Speaking of contrast setting, I just noticed that it appears in the menu (but does nothing, of course) when PCD8544 is used with m firmware.