Recent content by ttsky

Hi every one, I placed a multimeter probe across the terminals of a 1.5 v alkaline battery and saw 2 M Ohms, I did the same across a mV power supply at 1.5 volts and got little below 1.5 K ohms. I don't understand what makes them have diffrent resistance, and exactly why? I did this because I...

Yes two leads, when both are connected i see a rise in sensor reading from the analyzer, and when i take both leads off the reading drops. i can recreate this with only the ground lead. i have selected between 10M and >10G ohms input resistance on the meter, both with same results. it feels as...

Hi every one, I have a HP 34401a meter that is causing some issues with a high impedance sensor input. when I place only the ground wire ( black ) to the input circuit ground, the sensor reading jumps quiet dramatically, this does not happen if i place only the Red wire. I have tried...

well, this is more info than I bargained for. Thanks a lot every one!

I just did some tests on the device and recorded the ADC values and PPM outputs, it really shows the averaging effects talked about previously.

I am not the designer, so i can't change any thing. it was designed initially for larger input, but specs changed and it was hurried for the uA sensors, so I have to make sure it works. so far it is very unstable and i want to pin the cause of it, from my knowledge so far it seems the 16 bit...

Thanks for the reply, is the 16 bit in the title not indicating the steps of the quantizer? i saw no mentioning of these calculations in the data sheets. can you elaborate why the / 32 and /Sqrt(4) ?

Hi every one, I am examining a prototype device that is designed to analyse current from an electrochemical O2 sensor (current source), The sensor will output 1.124 uV per PPM (cross 47 ohms @0.023 uA), and has acuracy of +- 2 PPM, with max 1000 PPM. it ueses 16 bit Sigma Delta ADC with...

Thank you for reply, There are no limitations on external circuits, however if i don't have to then i wont, i will explore those options and post an update soon. thanks

Hi all, my task is to measure the charge time of an RC circuit with a counter using FPGA, once the cap is charged, i must discharge it again for next input. Idea is to discharge it with a signal from FPGA, but what sort of circuit would allow this without discharging the cap prematurely...

happened to me last semester, my favourite subject is the one I know and have practiced over and over in, which means towards the end of the semester when exam prep starts, I get pretty tired of looking at the same problem and neglect studying it, because I felt confident with them at some...

thank you for that, this topic opened a can of loop holes in my algebra! really appreciate your help. understand it now!

we spent last semester doing just that, I am only studying ahead so I have yet to find out why myself. i have heard it is important for EE students, which is what I am.

I don't see how this came about. can you elaborate?

This is more of a pre calc question but it dose however come from diff eqs, just in case I have made fundamental mistakes, i have posted it here. I have been studying this topic for few days by myself, never had any problems with algebra until here. really appreciate all of your help...