# Elements of Electrical Engineering

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### Elements Of Electrical Engineering:

Elements Of Electrical Engineering SEM-II A.L.A. Mechanical engineering Div. - A C. K. Pithawala College of Engineering & Technology

### GROUP – A7:

GROUP – A7 Name Roll Number Enrolment Number Patel Brijesh 122 160090119058 Desai Jainish 123 160090119011 Tankariya Hardik 126 160090119117 Pathak Aloknath 131 160090119085 Lalluwadia Yash 135 160090119039

Topics Covered

### Charging and discharging of capacitor:

Charging and discharging of capacitor

### Circuit of process charging and discharging:

Circuit of process charging and discharging

### When switch to A : Charging Process Curve:

When switch to A : Charging Process Curve t = 5 

### Formula For Charging Process:

Formula For Charging Process Time constant :-  = CR Initial Charging current:- I max = V/R Charging voltage of capacitor:- V c = V max (1 – e -t/ ) Charging current:- I = I max (e -t/ ) Initial rate of change in potential difference:- dV c / dt = V/CR Time when capacitor fully charge:- t = 5  Energy stored:- E = ½ CV max 2

### When switch to B : Discharging Process Curve:

When switch to B : Discharging Process Curve

### Formula For Discharging Process:

Formula For Discharging Process Time constant:-  = CR Initial discharging current:- I max = V/R Discharging voltage of capacitor:- V c = V max (e -t/ ) Discharging current:- i = - I max (e -t/ ) Initial rate of change in potential difference:- dV c / dt = V/CR Time when capacitor decreases charge:- t = 5 

### Hysteresis and Eddy Current losses:

Hysteresis and Eddy Current losses An eddy current is an electric current set up by an alternating magnetic field. These losses arise from the fact that the core itself is composed of conducting material, so that the voltage induced in it by the varying flux produces circulating currents in the material. Eddy current loss depends upon the rate of change of flux as well as the resistance of the path, it is reasonable to expect this loss to vary as the square of both the maximum flux density and frequency. If the core is solid and made up from ferromagnetic materials, it effectively acts as a single short-circuited turn. Induced eddy currents therefore circulate within the core in a plane normal to the flux, and cause resistive heating of the core material .

### Slide11:

During each A.C. cycle, current flowing in the forward and reverse directions magnetizes and demagnetizes the core alternatively. Energy is lost in each hysteresis cycle within the magnetic core. Energy loss is dependent on the properties (e.g. coercively) of particular core material and is proportional to the area of the hysteresis loop (B-H curve).

### Energy stored in Magnetic fields.:

Energy stored in Magnetic fields. Power delivered by an inductor Work done to increase the current in an inductor The energy stored in an Inductor Comparison to the Energy stored in a Capacitor Energy stored in a Solenoid

### Power Delivered by an Inductor:

When an inductor carries a current, an EMF is induced:- The power delivered by the inductor is:- The work done to increase the current in the inductor from zero to the value I is: Power Delivered by an Inductor (from Faraday’s Law)

### Energy Stored in the Magnetic Field of an Inductor (Solenoid):

Energy Stored in the Magnetic Field of an Inductor (Solenoid) IN an inductor of inductance L, carrying a current I, which is charging at a rate of dI / dt , is: The Energy stored in a Capacitor is:

### Slide15:

If the Energy stored in the inductor is: The energy stored in a Solenoid is: The energy density of an N-turn solenoid is:

### Thank you:

Thank you 