Recent content by green-fresh

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    Questions about bjt amplifier circuit

    yes this is what i mean. yea exactly this is what i must do and like what i asked: i find after googling about small signal model that i must at AC consider every capacitor as "short circuit" and also the power source so R_L and R_C have two commen point (one at C and one at GRD)so...
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    Questions about bjt amplifier circuit

    hi all i have some questions about a commen emmiter bjt amplifier circuit . if i had this circuit : and i want to find the ripple of voltage in outout : i will use this equation : V_{O(p-p)}=2I_{CQ} (R_L || R_C) but why i put R_L || R_C not R_L || R_C + R_E or how i conclude that...
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    Calculation the resistance of a spherical shape

    thank you i think it is solved now .
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    Calculation the resistance of a spherical shape

    hello there! I was reading about ohm rule in a MIT physics course and they calculate the resistance of a nested spherical shells like this : and they but the microscopic form of ohm's law which is : J=\sigma_q E and I=A J so I=(4 \pi r^2 ) (\sigma_q E) and E=-\frac{\partial...
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    Electric field between bands in semiconductors

    yes! I'm sorry you are right could i have an electric field between negative charge and positive charge even if there isn't a space between them . and is it correct that: the direction of this field is,i know from positive to negative , from CB(conduction band) to VB ?
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    Electric field between bands in semiconductors

    i read in an online course about semiconductors that electric field between E_c and E_v given by: E=\frac{dE_c}{q dx} and i know the general form of electric field is : E=\frac{k.q_0.q}{r^2} and what is the direction of this field ,i know from positive to negative , from E_c to E_v...
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    Nodal analysis physical problem

    yes! thank you very much dlgoff this is what i wanted to hear
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    Nodal analysis physical problem

    thank you dlgoff but i know how to do analyzing using this method but i can't understander the case of connecting the circuit to ground without eletrons going up to circuits and have influence to other voltages
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    Nodal analysis physical problem

    thank you berkeman for this useful informations as what 'waht' said: and from this to definitions i can tell you exactly what i mean: when i attach the node to ground i had zero voltage in this node . physically the electrons must go from the smaller voltage point(v_{ground}=0) to the...
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    Nodal analysis physical problem

    in the nodal analysis -one of ways of analysis DC circuit - i couldn't understand the physical roots of this way . i mean how could i make the voltage of a node equal to zero by make it as a reference point without having any effects on the voltage(electric potential) of the rest nodes ...
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    Understanding Experimental Error

    kote! thank you very much:smile: i think this resource is much better than what i found and i will try to get a book about number and error analysis . Bob S sorry but what is this case is different from: \Deltav/v =\Deltaa/a + \Deltab/b + \Deltac/c where delta a is known delta b is...
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    Understanding Experimental Error

    hi everyone ! when we say (for example)a,b and c are the dimension of Parallelogram a=2.267+- 0.002 cm b=3.376+-0.001 cm and c=0.207+-0.001 cm dose that means that we used equipment to calculat a and another to calculate b and c ? because i know that delta a or b or c is half...
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    Does anyone have any recommendations as to how to assign error to this?

    frequency of what ? of light wave or sound wave ? and about what is this experiment? because i now another way to calculate errors in experiments (with out drawing but in need equation or something like that ).
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