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    Questions about charging lithium batteries (to prolong battery life)

    Hi, I want to know what is the proper methods to prolong lithium battery life: When Should I recharge the battery(at any level 90%, 70 or 40 etc)? Should I charging it fully at 100%? is true that discharging battery below 20% once each month is useful to boost battery life?
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    How to record two signals simultaneous(by using ADC) ?

    Hi: I need to record a two analog signals, by using an ADC(of 20 bits resolution or higher), the two signals are very weak signals of signal to noise ratio about -30 db, so the two signals are very effective by the noise. the problem is : how to record these two signals at the same...
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    Question about turing machine

    Hi: I read many articles about turing machine,but i still confused:confused: is a turing machine can only execute one program(hardwired) ? or it can execute many programs(like a conventional computer)? i asking about turing machine as shown in figure blew(not asking about universal TM...
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    A question about Qubit (number of states)

    Hi I read this information about the Qubit: "N Qubits are equivalent 2^N classical bits (2^N states)" But I couldn't understand that, because I know that each single Qubit could be one and zero at the same time, so each single Qubit is equivalent two classical bits (two states) That...
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    Question about ECG filters

    Hi guys i built an ECG system(preamplifier and filters), but i faced a problem in the filters: the standard of ECG filters is 0.1 Hz cuttoff frequency for highpass filter and 100 Hz for lowpass filter but i only obtain a good ECG signal when i make the cuttoff frequency of highpass filter...
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    Question about design active filter

    hi: i designed an active low-pass filter,but i don't know if it correct method or not i want fc=200 Hz and n(order)=4. i use this method: by let C=100 nF and use this equation "fc=1/(2*pi*C*R1)" i get R1= 8 Kohm,R2=R1 this is for one stage to get filter of 4 order,i repeat that...
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    Why does the ICs(AD620AN) gets damaged?

    Hi: I bought six instrument amplifiers(AD620AN), i tested these ICs,all ICs was work properly but later the ICs gets damaged(5 five of 6 ICs gets damaged) i was very carefully(by reading datasheet) about power supply and input voltage i used this circuit(to make AD620AN work as just...
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    Question about differential amplifier(isolated input signal)

    Hi: when using op amp as differential amplifier, can it used for input signal isolated from power supply of that op amp? as this figure: http://uploadpic.org/storage/2011/k9bEue1EtqkWGlH5yTDN3198.jpg so if the input signal is sinewave 5 Vp.p, will be the output of this op amp...
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    Will i need amplifier in this case?

    Hi: i have ADC(analog to digital) has a resolution 12 bits and the input range is from +50mV to -50mV, this men the precision is about 24uV i want to use this ADC for a signal has Vp.p from 0.7mV to 1mV so can i use this ADC directly?or i must use amplifier ??
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    Medical Question about ECG signal

    Hi: when we use Limb lead placement(RL,LL,RA and LA electrodes) we can obtain six signal: I,II,III,aVR,aVL and aVF The question is: Are These six signals shown(on paper or screen) individually? or there is another method?
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    Measuring ECG signals

    Hi guys:I have a project to design ECG i want to calculate the six leads(I,II,III,aVR,aVL and aVF) by this method: i will measure the voltage of three probe or electrode(RA,LA and LL) RL as a reference by using DAC(digital to analog converter) the DAC connected to PC computer, and...
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    Implementation low pass filter on array

    hi guys: if i have signal(YT) consist of two frequencies(30 and 300 Hz),as the following: t=0:1/1000:1; Y30=sin(2*pi*t*30); Y300=sin(2*pi*t*300); YT=Y30+Y300; i want remove the frequency of 300 Hz from(YT) by using low pass filter so how can i do that(by using matlab command)?
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    Is the earth has value 0V?

    hi guys i like this forum:smile: if we have a transformer(star type),,has three phase(a,b and c) and has also neutral , let Vphase=220 R.M.S if the neutral of this transformer is not grounding"neutral hasn't any contact with earth" my question is: if we put a voltmeter between the earth...
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