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    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...
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    Voltage meter load

    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...
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    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...
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    16 bit sigma delta ADC question

    well, this is more info than I bargained for. Thanks a lot every one!!
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    16 bit sigma delta ADC question

    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.
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    16 bit sigma delta ADC question

    I am not the designer, so i cant 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 just...
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    16 bit sigma delta ADC question

    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) ?
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    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...
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    RC circuit, discharge with digital signal from FPGA

    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
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    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...
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    BJT voltage on the emitter question

    aha! that makes alot of sense, thanks alot!
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    MIT 6.002x : open for everyone

    thanks alot !!
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    How does alternating current produce a sine wave over time?

    start revising complex numbers ;P thats how you will understand this the best.
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    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...
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