0
What is the value of a resistor when current and voltage are both zero?
Wiki User
∙ 12y ago
The value can be anything.
As long as the resistance is not zero, if the voltage across the resistor is zero the current through the resistor will also be zero.
The relevant equations is...
Voltage = Resistance x Current
In the special case of superconductivity, the resistance is zero and you can have a current even if the voltage is zero.
AnswerResistance is affected by the length of a material, its cross-sectional area, and its resistivity (which, in turn, is affected by temperature). The resistance of a resistor, therefore, is not affected by either voltage or current.
Wiki User
∙ 12y ago
Add your answer:
Earn +20 pts
Does a resistor drop current or voltage?
A resistor drops both voltage and current, however the term "drop" is generally used to indicate a voltage or current drop across the device, so it is more correctly stated that a resistor drops voltage, by allowing the current in the circuit to decrease.
How does the voltage divider biasing network got its name?
Because that's what it is. It is a voltage divider. Two resistors in series will have the same current through them. This is Kirchoff's current law. By Ohm's law, then, the voltage across each resistor is current times resistance, and this is a linear function. By Kirchoff's voltage law, then, the total voltage drop across both resistors is equal to the input voltage. Two resistors of the same value will divide the voltage in half. One resistor (the top resistor) having twice the resistance of the other, will divide the voltage to a third. If the top resistor is nine times the bottom resistor, the divider produces one tenth. And so on and so forth...
Will current flow in a higher resistance or in lower resistance if they are connected in parallel to a voltage source?
Current will always flow in both resistors, but the one with the lower resistance will have more current flow through it. The value of the current in each resistor is calculated by dividing the voltage of the source by the resistance of the individual resistor. As long as the capability of the power source isn't exceeded, the current through each resistor isn't affected by the presence of the other resistor. Said another way, if two resistors are connected in parallel across a source, neither one "cares" that the other resistor is connected across the source. The two resistors work independently.
If the resistance in the circuit is increased what will happen to the current and voltage?
* resistance increases voltage. Adding more resistance to a circuit will alter the circuit pathway(s) and that change will force a change in voltage, current or both. Adding resistance will affect circuit voltage and current differently depending on whether that resistance is added in series or parallel. (In the question asked, it was not specified.) For a series circuit with one or more resistors, adding resistance in series will reduce total current and will reduce the voltage drop across each existing resistor. (Less current through a resistor means less voltage drop across it.) Total voltage in the circuit will remain the same. (The rule being that the total applied voltage is said to be dropped or felt across the circuit as a whole.) And the sum of the voltage drops in a series circuit is equal to the applied voltage, of course. If resistance is added in parallel to a circuit with one existing circuit resistor, total current in the circuit will increase, and the voltage across the added resistor will be the same as it for the one existing resistor and will be equal to the applied voltage. (The rule being that if only one resistor is in a circuit, hooking another resistor in parallel will have no effect on the voltage drop across or current flow through that single original resistor.) Hooking another resistor across one resistor in a series circuit that has two or more existing resistors will result in an increase in total current in the circuit, an increase in the voltage drop across the other resistors in the circuit, and a decrease in the voltage drop across the resistor across which the newly added resistor has been connected. The newly added resistor will, of course, have the same voltage drop as the resistor across which it is connected.
What is the relationship of current through the resistor and inductor in the LR parallel circuit?
When they are in parallel the same voltage appear across both. The resistor carries a current of V/R, the inductor carries a current of V/(jwL). So the current in the inductor is 90 degrees behind in its phase.
What you consume in home current or voltage?
Power is contituted by both current and voltage So we consume both current and voltage
Explain thevenin's theorem?
Thévenin's theorem for linear electrical networks states that any combination of voltage sources, current sources, and resistors with two terminals is electrically equivalent to a single voltage source V and a single series resistor R #wikipediaactually i will explain you the way to solve problems applying this theorem consider a large network and in that network assume any resistance R about which you are asked o find the current and voltage-drop. now follow the steps below carefully1. remove the specific resistor from the circuit (open the resistor) and find the voltage across both the points(or even parallel to both the points) where the resistor is opened this is called VTH (this is called thevenin's voltage).Also dont forget to open the current sources if present.2. now to calculate the effective resistance as seen from the opened resistor short all the voltage sources and open all the current sources. and assume an arbitrary voltage V in the place of the opened resistor find current through the branch by mesh analysis and the ratio of voltage and current gives you the effective resistance fo the circuit as seen from the opened resistor. this is called Rth (thevenin resistance).now , after getting the values of VTH,RTH construct a circuit in which the given resistance R and RTH arein series with the voltage source VTH , and the so called found current is the current flowing through R in the actual circuit
What you get from mains voltage or current?
You get power, which is voltage * current (so both!).
Why don't capacitor discharge completely in an RC circuit?
Capacitors do not get "full" like a glass of water. The current into a capacitor is the rate of change of charge, so it's equal to C * dV/dt or something. If the voltage is constant, there's no current. If the voltage on both sides of the resistor is the same, there's no current through the resistor and hence into the capacitor, so that's the steady-state - what you call "full" - the capacitor charged to the supply voltage.
When an inductor and resistor are connected in parallel by how many degrees is the current flow through the resistor out of phase with the current flow through the inductor?
When a resistor and an inductor are both connected to an AC supply, the current in the resistor is in phase with the voltage, while the current in the inductor is a quarter-cycle (90 degrees) behind. Supposing they both draw 1 amp on a 12-volt AC supply. The resistor will dissipate 12 watts, while the inductor will dissipate no power. Any power that enters the inductor comes back to the generator in a later part of the cycle. But the current drawn from the supply is 1.414 amps, so this would be a load with a power factor of 0.707.
Why does one trace of the oscilloscope traces have to be inverted to display the voltage and current with the correct phase relationship?
One trace of the oscilloscope traces have to be inverted to display the voltage and current with the correct phase relationship because you are probably connecting to both sides of a small resistor in series with the load. The supply side shows voltage, while the load side shows voltage drop for the load. You are showing differential voltage across the resistor in the second trace and, of course, its negative.If, however, you are using a current probe, perhaps a clamp-on ammeter, I would question if you have it connected correctly.
2ohm and 4ohm resistor are connected in series to a 12V battery what is the current through each resistor and use Ohm's law 2 show that the voltage drops across the individual resistors add up to 12V?
To answer this question, you need not only Ohm's law, but also Kirchoff's current and voltage Laws.Kirchoff's current law say the current at every point in a series circuit is the same. Lets call that current i.Ohm's law say voltage is resistance times current. That means the voltage across each resistor R1 and R2 is V1 = R1i and V2 = R2i.Kirchoff's voltage law says that the signed voltage drops around a series circuit add op to zero. This means that the voltages V1 and V2 must add up to be be equal to 12. This means that R1i + R2i = 12. This means that i = 12/(R1 + R2). But, hey, you say, this is just Ohm's law! This means that the current through the circuit is 2A. It also means that the resistance of two resistors in series is simply the sum of their resistance.Now that we know the current, we can calculate each resistor's voltage. V1 = R1i = (2)(2) = 4, and V2 = R2i = (4)(2) = 8. Crosscheck 4 + 8 = 12, so the two voltages do add up to twelve volts, as expected.In summary: The current through both resistors is 2A. The voltage across the 2 ohm resistor is 4V. The voltage across the 4 ohm resistor s 8V.
