But after everything, if i connect the cellphone, the output voltage of the joule thief wil start fluctuating, thereby making the phone to write "charging" and stops again, and writes "charging" again and stops continously.
The circuit i used is the one i saw in ur blog titled "1. Please help! But it refuse to work. What could be wrong? Ok sir! It is about pieces of the RGB LED can produce 6watt, and pieces of the IR-LED can produce 6watt for charging the battery from a cellphone, and its quantity is too much, so i want to reduce the quantity, hence the wattage by connecting the Li-ion cellphone battery directly to the output of the proposed LED-based solar cell.
My questions are: What is the maximum voltage and current that is safe for charging the cellphone battery directly? And what quantity of the LEDs could be able to produce the power for charging the battery? And what is the normal power for charging the battery directly from the LED-based solar cell without using a cellphone or any charger circuit? Either your meter is faulty or you seeing it wrongly. It could be uA microamps that you are seeing, check it properly.
Tueresueco, there are plenty of books, so I am not sure which one may be suitable for you, alternatively you can join my personal forum and get full tutorial and help from me.
Greetings Mr. Swagatam Majumdar. Your email address will not be published. Notify me via e-mail if anyone answers my comment.
You'll also like: 1. AC Theory Modules 2. Capacitors 3. Inductors 4. DC Transients 5. Phase and Phasors 6. Reactance 7. Impedance 8. LCR Series Circuits LCR Parallel Circuits Module 3. Google Ads. Section 3. Top of Page. When the voltage becomes negative at point a, the current begins to decrease; it becomes zero at point b, where voltage is its most negative.
The current then becomes negative, again following the voltage. The voltage becomes positive at point c where it begins to make the current less negative. At point d, the current goes through zero just as the voltage reaches its positive peak to start another cycle. Current lags behind voltage, since inductors oppose change in current. Changing current induces an emf. This is considered an effective resistance of the inductor to AC. X L is called the inductive reactance.
Therefore, the phasor representing the current and voltage would be given as in. Phasor Diagram : Phasor diagram for an AC circuit with an inductor. Resonance is the tendency of a system to oscillate with greater amplitude at some frequencies than at others.
To study the resonance in an RLC circuit, as illustrated below, we can see how the circuit behaves as a function of the frequency of the driving voltage source. Substituting the definitions of X L and X C yields:. This is also the natural frequency at which the circuit would oscillate if not driven by the voltage source.
Resonance in AC circuits is analogous to mechanical resonance, where resonance is defined as a forced oscillation in this case, forced by the voltage source at the natural frequency of the system. A variable capacitor is often used to adjust the resonance frequency to receive a desired frequency and to reject others. The two curves are for two different circuits, which differ only in the amount of resistance in them.
The peak is lower and broader for the higher-resistance circuit. Thus higher-resistance circuits do not resonate as strongly, nor would they be as selective in, for example, a radio receiver. Current vs. Frequency : A graph of current versus frequency for two RLC series circuits differing only in the amount of resistance. Both have a resonance at f0, but that for the higher resistance is lower and broader.
The driving AC voltage source has a fixed amplitude V0. If current varies with frequency in an RLC circuit, then the power delivered to it also varies with frequency. However, the average power is not simply current times voltage, as is the case in purely resistive circuits. As seen in previous Atoms, voltage and current are out of phase in an RLC circuit. At other frequencies, average power is less than at resonance, because voltage and current are out of phase and I rms is lower.
The fact that source voltage and current are out of phase affects the power delivered to the circuit. It can be shown that the average power is. I t and V t are current and voltage at time t. Power factors near 1 are desirable when designing an efficient motor, for example.
The inductor and capacitor have energy input and output, but do not dissipate energy out of the circuit. Rather, they transfer energy back and forth to one another, with the resistor dissipating the exact amount that the voltage source gives the circuit.
This assumes no significant electromagnetic radiation from the inductor and capacitor such as radio waves. The circuit is analogous to the wheel of a car driven over a corrugated road, as seen in. The regularly spaced bumps in the road are analogous to the voltage source, driving the wheel up and down. The shock absorber is analogous to the resistance damping and limiting the amplitude of the oscillation.
Energy within the system goes back and forth between kinetic analogous to maximum current, and energy stored in an inductor and potential energy stored in the car spring analogous to no current, and energy stored in the electric field of a capacitor. The shock absorber damps the motion and dissipates energy, analogous to the resistance in an RLC circuit. The mass and spring determine the resonant frequency.
Privacy Policy. Skip to main content. Search for:. AC Circuits. Inductance Induction is the process in which an emf is induced by changing magnetic flux, such as a change in the current of a conductor. Learning Objectives Describe properties of an inductor. Key Takeaways Key Points In the case of electronics, inductance is the property of a conductor by which a change in current in the conductor creates a voltage in both the conductor itself, called self-inductance, and any nearby conductors, called mutual inductance.
Mutual inductance is illustrated by. M is the same for the reverse process. Key Terms mutual inductance : The ratio of the voltage in a circuit to the change in current in a neighboring circuit. Inductor Symbol. RL Circuits An RL circuit consists of an inductor and a resistor, in series or parallel with each other, with current driven by a voltage source. Learning Objectives Describe current-voltage relationship in the RL circuit and calculate energy that can be stored in an inductor.
It takes time to build up stored energy in a conductor and time to deplete it. This represents the time necessary for the current in a circuit just closed to go from zero to [latex]0. Most common applications use a time-varying voltage source instead of a DC source. Learning Objectives Explain the benefits of using a phasor representation. Key Takeaways Key Points When a capacitor is connected to an alternating voltage, the maximum voltage is proportional to the maximum current, but the maximum voltage does not occur at the same time as the maximum current.
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