What is the relation between frequency and voltage | All About Circuits
Hi How can it be that the frequency is 50 Hz and voltage is V in the wall where creates that 50 There is a formula says: V=(f*h)/e. One of the earliest disputes in power generation and distribution was electrical safety. Alternating current (AC) is an electric current which periodically reverses direction, in contrast to direct current (DC) which flows only in one direction. Alternating current is the form in which electric power is delivered to . Even at relatively low frequencies used for power transmission (50 Hz – 60 Hz), non- uniform distribution. The relationship between wattage, voltage and frequency is governed by circuit impedance. If one resistor exist, Rt is the value of that resistor. Calculate the reactance from the inductor, or XL, using the formula XL = 2 * pi * f * Lt where pi is .
Originally posted by ellea Nov 25 As for the ratio. Man that's a long euation to solve: First of all, by voltage, it wasn't clear whether ledjr was referring to instantaneous or RMS? I'm guessing sinusoidal only.
The voltage for some given frequency varies as a function of time described by the following equation: You can see that changing the frequency only affects when in time any specified voltage occurs. At any time t the absolute value of the voltage never exceeds Vp value since the sin wt is always less than or equal to 1 and greater than or equal to Now, I'm guessing that ledjr probably was curious about what he'd measure with an AC voltmeter if the frequency only is changed.
That is, he'd like to get some average or effective measurement comparisons for different frequencies. So he needs to know how AC voltage measurements are obtained. Therefore, before proceeding, I think ledjr really should read the article http: He should notice that what we normally mean by "voltage" as used to represent some meaningful AC aggregate measurement value is either a "true" or cleverly simulated RMS Root Mean Squared value.
To understand why this is, we should review some of the relevant equations, including: We should follow the circuit through one cycle of the voltage to figure out what happens to the current.
Step 1 - At point a see diagram the voltage is zero and the capacitor is uncharged. Initially, the voltage increases quickly.
The voltage across the capacitor matches the power supply voltage, so the current is large to build up charge on the capacitor plates. The closer the voltage gets to its peak, the slower it changes, meaning less current has to flow. When the voltage reaches a peak at point b, the capacitor is fully charged and the current is momentarily zero. Step 2 - After reaching a peak, the voltage starts dropping. The capacitor must discharge now, so the current reverses direction. When the voltage passes through zero at point c, it's changing quite rapidly; to match this voltage the current must be large and negative.
Alternating current - Wikipedia
Step 3 - Between points c and d, the voltage is negative. Charge builds up again on the capacitor plates, but the polarity is opposite to what it was in step one. Again the current is negative, and as the voltage reaches its negative peak at point d the current drops to zero. Step 4 - After point d, the voltage heads toward zero and the capacitor must discharge. When the voltage reaches zero it's gone through a full cycle so it's back to point a again to repeat the cycle.
The larger the capacitance of the capacitor, the more charge has to flow to build up a particular voltage on the plates, and the higher the current will be. The higher the frequency of the voltage, the shorter the time available to change the voltage, so the larger the current has to be. The current, then, increases as the capacitance increases and as the frequency increases.
Usually this is thought of in terms of the effective resistance of the capacitor, which is known as the capacitive reactance, measured in ohms. There is an inverse relationship between current and resistance, so the capacitive reactance is inversely proportional to the capacitance and the frequency: A capacitor in an AC circuit exhibits a kind of resistance called capacitive reactance, measured in ohms.
This depends on the frequency of the AC voltage, and is given by: Note that V and I are generally the rms values of the voltage and current. Inductance in an AC circuit An inductor is simply a coil of wire often wrapped around a piece of ferromagnet.
The reason for this has to do with the law of induction: Applying Kirchoff's loop rule to the circuit above gives: As the voltage from the power source increases from zero, the voltage on the inductor matches it. With the capacitor, the voltage came from the charge stored on the capacitor plates or, equivalently, from the electric field between the plates. With the inductor, the voltage comes from changing the flux through the coil, or, equivalently, changing the current through the coil, which changes the magnetic field in the coil.
To produce a large positive voltage, a large increase in current is required.
How to Find Wattage With Voltage & Frequency | Career Trend
When the voltage passes through zero, the current should stop changing just for an instant. When the voltage is large and negative, the current should be decreasing quickly. These conditions can all be satisfied by having the current vary like a negative cosine wave, when the voltage follows a sine wave.
How does the current through the inductor depend on the frequency and the inductance? If the frequency is raised, there is less time to change the voltage. If the time interval is reduced, the change in current is also reduced, so the current is lower. The current is also reduced if the inductance is increased. As with the capacitor, this is usually put in terms of the effective resistance of the inductor. This effective resistance is known as the inductive reactance.
This is given by: The unit of inductance is the henry.