Energy Stored By a Capacitor , Stray Capacitances , Flash Lamp

An ideal capacitor does not dissipate any of the energy supplied to it. It stores the energy in the form of an electric field between the conducting surface. A plot of the voltage , current and power to a capacitor during the charging phase is shown.
The power curve can be obtained by finding the product of the voltage and current at selected in stants of time and connecting the points obtained. The energy stored is represented by the shaded area under the power curve.Using calculus we can determine the area under the curve :



                    Wc=1/2CE2

In general   Wc=1/2CV2



Where V is the steady state voltage across the capacitor. In terms of Q


                   Wc=1/2C(Q/C)


or                Wc=Q2/2C


Stray Capacitances


  In addition to capacitors discussed so far in this lesson , there are stray capacitances that exist not through design but simply because two conducting surfaces are relatively close to each other. Two conducting wires in the same network have a capacitive effect between them as shown in electronic circuit capacitance levels exist between conducting surfaces of the transistor as shown in lesson we will discuss another element called the inductor  , which has capacitive effects between the windings.Stray capacitances can often lead to serious errors in system design if they are not considered carefully. 


Flash Lamp

      The basic circuitry for the flash lamp of the popular, inexpensive, through away camera is provided. The physical circuitry is on the next page. The labels added to identify broad areas of the design and some individual components. The major components of the electronic circuitry include a large 160microfarad 330v polarized electrolytic capacitor to store the necessary charge for the flash lamp, a flash lamp to generate the required light , a dc battery of 1.5v a chopper network to generate a voltage 
                  

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