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Transformers are used to increase the voltage and reduce the current in overhead power lines but wont increasing the voltage subsequently increase the current as resistance is a constant?
Ghuntu
You're assuming that the line is dead shorted. In that case, assuming zero source impedance, current would increase as well. In reality, source impedance often limits the very high voltage short circuit current to less than the lower voltage.
Think of it this way: I have a 120 volt, 5000 watt totally resistive load (no motors). At 120 volts, I am pulling 41.67Amps. Say the power plant supplying this load is 100 miles away, and the overhead power line (regardless of voltage level) has .01 ohms/mile resistance (total of 1 ohm resistance). If the power company tries to deliver power at 120 volts, instead of the 5000 watts I want, I will get 5000 watts, but the power company will have to generate (5000 + 1 * 41.67^2) = 6736 watts*.
If instead the power company steps the voltage up to say 13.8kV right outside my house (as close to the load as possible), total current at 13.8kV will be 362mA, so total power loss in transmission is .131watts (as opposed to 1736 at 120 volts).
From the 120 volt perspective, my 5000 watt load "looks like" 2.88 ohms, since P = V*I = V^2/R.
If we are looking at my house through a 13.8kV/120v transformer, the transformer has a turns ratio of 13800/120 = 115, thus increases voltage by 115 times, and decreases current by 115 times (from lowside to highside). Thus from the 13.8kV perspective, my 5000 watt load "looks like":
P = V^2/R = (120 * turns_ratio)^2/R = (120*115)^2/R = 13800^2/R
R = 38,088 ohms.
The transformer changes voltage and current inversely to each other; this results in a change in apparent impedance relative to the highside and lowside of the transformer.
*This is assuming the power company is delivering voltage at 120 volts through the line, and uses some sort of reactive power to compensate for the voltage drop through the line. This is often done by installing capacitor banks, or having generators closer to the load produce reactive power. The wasted transmission losses plus the cost of this extra equipment would result in higher power costs being passed on to customers.
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What will always increase voltage?
increasing resistance and keeping current constant
What actions will always increase voltage?
increasing resistance and keeping current constant
The amount of current in a circuit can what by increasing the amount of resistance present in the circuit?
No it cant. Voltage = Current x Resistance. So at constant Voltage if the Resistance is increased, Current will reduce
How you increase current by keeping voltage constant?
If you are referring to a simple circuit, you could add resistance throughout it. Increased resistance means decreased current flow yet the same voltage.
You are monitoring electric current in a circuit. you notice the voltage increasing this mean's that?
Ohm's Law states that the current (I) flowing in a circuit is directly proportional to the applied voltage (E) and inversely proportional to the circuit's resistance (R).I = E/RAnother way of stating Ohm's Law is that the applied voltage (E) is directly proportional to both the current (I) and the resistance (R).E = IxR.So, if the voltage (E) is increasing, then either:if you know the resistance (R) is staying constant then the current (I) must be increasing - which you would see because you are monitoring it! or, if the current (which you are monitoring) is actually staying constant, then, for the voltage to be able to increase:the circuit's resistance must be increasing orthe increasing voltage could be caused by a combination of both increasing current and increasing resistance!
How the current in a circuit changes if the voltage in the circuit is decreased and the resistance remains the same?
If the ratio of voltage to current is constant, then the circuit is obeying Ohm's Law. If the ratio changes for variations in voltage, then the circuit does not obey Ohm's Law.
How does wire thickness affects resistance?
Increasing wire thickness decreases its resistance, while increasing its length increases its resistance. Provided the voltage between the ends of the wire is constant, the current through it is inversely proportional to its resistance.
Effect on voltage as current increases through constant resistance?
If the current is held constant, the voltage will decrease.
What is constant resistance?
A resistance that doesn't change.
How does Lenz's Law explain power loss in transformers?
It doesn't, really. The power loss in transformers is broken down into copper loss and iron loss. The copper loss comes from the resistance of the windings in the transformer and depends on the load current, while the iron loss in the magnetic core depends on the magnetic flux density and is constant if the supply voltage is constant.
What is time constant of capacitor when resistance is zero?
Time constant in an RC filter is resistance times capacitance. With ideal components, if the resistance is zero, then the time constant is zero, not mattter what the capacitance is. In a practical circuit, there is always some resistance in the conductors and in the capacitor so, if the resistance is (close to) zero, the time constant will be (close to) zero.
When current remains constant and resistance increases the voltage in the circuit will?
The physical equation governing voltage is V = IR, where V is voltage, I is current, and R is resistance. If V remains constant while R is increased, I or current must decrease. Increasing the resistance in a circuit is simply introducing a material that further resists or impedes the electron flow (current), thus current decreases.
