Measuring VSS (SOLVED)

[truhlik_fredy]

It looks overkill to me. Did you try the circuit I posted using a few logic gates? if it doesn't work it can be tweaked.

Your design is in the to-do as well And the last solution what I want try is with MAX9924, it on the way and I desperate to get it ASAP because I'm curious how well it will work.

All of that can be done using a single comparator IC such as the LM393 or LM311.

I don't argue, but that chips I have on hand, and don't have lm393 / lm311 .

[Zero999]

It can also be done with a LM324 and half as many resistors. It's basically the same with the LM393 except you need to add a pull up resistor to the output and can omit the protections diodes which are built-in to the IC.

[truhlik_fredy]

It can also be done with a LM324 and half as many resistors. It's basically the same with the LM393 except you need to add a pull up resistor to the output and can omit the protections diodes which are built-in to the IC.

I'm little worried about that part (pull up, or feedback), I felt much more in comfort when there is a sort of buffer, still the signals need to go to another instrument etc..

[Zero999]

I either forgot to attach the schematic to my previous post or there was a problem with the server.

Here's what I had in mind. If you opt for the LM393, you save the diodes but need an extra pull-up resistor.

[Eliminateur]

truhilik, looking for parts to design a circuit for naother project, i found something that might interest you: http://www.national.com/ds/LM/LM193.pdf page 11
very simple zero-crossing detector with a jelly-bean LMx93 series comparator

[truhlik_fredy]

I either forgot to attach the schematic to my previous post or there was a problem with the server.

Here's what I had in mind. If you opt for the LM393, you save the diodes but need an extra pull-up resistor.

Thanks I will order LM393 and I will try it later, now I received the Maxim 9924 samples so I want to try them out first.

[truhlik_fredy]

truhilik, looking for parts to design a circuit for naother project, i found something that might interest you: http://www.national.com/ds/LM/LM193.pdf page 11
very simple zero-crossing detector with a jelly-bean LMx93 series comparator

Thanks that nice, I was thinking about zero crossing earlier, I will order LM193 as well. It looks like to be good idea to have couple different kinds of opamps, I can't stock just LM324 and hope that everything will be solvable with it. 

[truhlik_fredy]

I want just go back and thanks for everyones suggestions. Today I finished and tested the design with the Max9924 (the uMax 10 is not the easiest to solder) and it works just beautifully. I wanted to test all approaches suggested, but now it impressed me so much that I will keep this design. I will test all others, but just when I will be bored and be curious just to see how they works. But definitely for everyone else in similar situation, the Max 9924 is very good choice to go, I used the reference design for A2 mode.