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When a capaciter is charged through a resistor it shows maximum current at first and slowly it decreases why?
Wiki User
∙ 12y ago
Because the voltage across the capacitor is initially zero, making the voltage across the resistor maximal. As the capacitor charges, the voltage across the resistor decreases, with an accompanying reduction in current. At maximum charge, the voltage across the resistor is zero, and thus there is no current.
The equation of a capacitor is ...
dv/dt = i/c
... meaning that the rate of change of voltage, in volts per second, is proportional to current, in amperes, and inversely proportional to capacitance, in farads.
Set this up into a series charging circuit, replacing the i term with (V-Vt) / R, solve the differential equation, and you get ...
Vt = VSource (1 - e-t/RC)
.... where Vt is voltage at some time t, and RC is the time constant, resistance times capacitance.
The is the DC state answer. AC circuits are a whole other issue, and require different analysis, though the fundamental equation remains the same.
Wiki User
∙ 12y ago
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If a resistor decreases in value what will happen to the current through the resistor?
If the voltage applied across the resistor remains constant, then as the resistance of the resistor decreases, the current through it will increase. Consider Ohm's Law: E = IR In this formula, in order for 'E' to remain constant as 'R' decreases, 'I' must increase. Another form of Ohm's Law: I = E/R If 'E' remains constant, then the value of the fraction increases as its denominator 'R' decreases.
What happen to current when paralle resistor added?
For the individual resistor, the current is constant, regardless of any other resister that's attached to it in parallel. The current that results from all the resistors combined decreases as the resistance of one or more of the resistors increases.
How does load current vary with the load resistance?
Their relationship is only dependent on the voltage lost across that resistor; voltage equals resistance times current, so increasing the current for a given voltage will require a decrease in the resistance, and vice versa.
How do resistance behave in parallel circuit?
in a parallel circuit resistance decreases increasing the current.
How does the current in a resistor change if the voltage across the resistor is increased by a factor of 2?
It decreases by a factor of 4
If a resistor decreases in value what will happen to the current through the resistor?
If the voltage applied across the resistor remains constant, then as the resistance of the resistor decreases, the current through it will increase. Consider Ohm's Law: E = IR In this formula, in order for 'E' to remain constant as 'R' decreases, 'I' must increase. Another form of Ohm's Law: I = E/R If 'E' remains constant, then the value of the fraction increases as its denominator 'R' decreases.
What happen to current when paralle resistor added?
For the individual resistor, the current is constant, regardless of any other resister that's attached to it in parallel. The current that results from all the resistors combined decreases as the resistance of one or more of the resistors increases.
What happens when you use a smaller resistor in place of larger one?
as we can deduce from its name, the resistor "resists" to the current (the movement of the electrons) so as the value of the resistor increases, the current flowing through it decreases. so when you use a smaller resistor, the current increases, however the tension between its poles decreases ( due to the voltage divider law). remember that the shortcircuit is due to the small value of the current , so we need always to have a resonable resistance on the circuit..... but not too high because joule losses we'll be more significant !! hope i've been clear :D
What will happen to the other resistor if the number of resistor decreases?
the voltage across that resistor will increase if it is in series with the other resistors. the current through that resistor will increase if it is in parallel with the other resistors.
How does load current vary with the load resistance?
Their relationship is only dependent on the voltage lost across that resistor; voltage equals resistance times current, so increasing the current for a given voltage will require a decrease in the resistance, and vice versa.
Why do resistor voltage decrease while capacitor discharges?
The reason why resistor voltage decreases while a capacitor discharges is because the resistor acts like a source of electrical energy. As the capacitor discharges, it draws energy from the resistor, which causes the voltage across the resistor to decrease. This is because the capacitor is acting like a drain, and is taking energy out of the resistor, thus causing the voltage across the resistor to decrease. The resistor and capacitor work together in order to create a discharge circuit. This is done by connecting the capacitor to the resistor, and then to a voltage source. The voltage source supplies the energy to the resistor, and then the resistor transfers this energy to the capacitor. As the capacitor discharges, it takes energy from the resistor, which causes the voltage across the resistor to decrease. In order to understand this process better, it is important to understand the basics of Ohm's Law. Ohm's Law states that the voltage across a resistor is equal to the current through the resistor multiplied by the resistance. As the capacitor discharges, it takes energy from the resistor, which means that the current through the resistor decreases, and therefore the voltage across the resistor will also decrease.
How do resistance behave in parallel circuit?
in a parallel circuit resistance decreases increasing the current.
How does the current in a resistor change if the voltage across the resistor is increased by a factor of 2?
It decreases by a factor of 4
A can be used to reduce the current in a circuit?
A resistor.
Is current is drop when it flowing through the resistor?
Current flows in loops, voltage drops across elements. With relation to current, what flows in, must flow out, so no, current is not dropped across a resistor, it flows through a resistor and voltage is dropped across the resistor.
What is a ballast resistor?
A ballast resistor is an electrical resistor whose resistance varies with the current passing through it, thus maintaining a constant current.
Basic concept of resistor?
resistor is to resists the flow of current
