# Search results

1. ### Battery and resistance

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 dont understand what makes them have diffrent resistance, and exactly why? I did this because I...
2. ### Voltage meter load

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...
3. ### 16 bit sigma delta ADC question

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...
4. ### RC circuit, discharge with digital signal from FPGA

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...
5. ### Laplace transform,partial fraction problem

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...
6. ### Mechatronic engineering

I am just about to complete first year mechatronics, love every thing so far. but i am starting to have some doubts about this course as I talk to more people about it, some lectures suggest that this course is very broad and dose not really go to things in depth, at the same time being one of...
7. ### BJT voltage on the emitter question

i got this example from our lecture notes, there is one thing i dont understand, When calculating Ve, he takes Vb and minus the Voltage drop across transistor, so 2V - 0.7V and gets 1.3 V for Ve, my confusion is why did he ignore Vc? should it not be (Vc + Vb)-0.7V ,so...