Energy Storage

 
Energy Storage

Capacitors used for energy storage Capacitors are devices which store electrical energy in the form of electrical charge accumulated on their plates. When a capacitor is connected to a power source, it accumulates energy which can be released when the capacitor is disconnected from the charging source, and in this respect they are similar to batteries. The difference is that a battery uses electrochemical processes to store energy, while a capacitor simply stores charge. As such, capacitors are able to release the stored energy at a much higher rate than batteries, since chemical processes need more time to take place. The amount of stored energy depends on the amount of charge that is stored on the capacitor’s plates. Alternatively, the amount of energy stored can also be defined in regards to the voltage across the capacitor. The formula that describes this relationship is: where W is the energy stored on the capacitor, measured in joules, Q is the amount of charge stored on the capacitor, C is the capacitance and V is the voltage across the capacitor. As seen from the above equation, the maximum amount of energy that can be stored on a capacitor depends on the capacitance, as well as the maximum rated voltage of a capacitor. The stored energy can be quickly released from the capacitor due to the fact that capacitors have low internal resistance. This property is often used in systems that generate large load spikes. In such cases, batteries cannot provide enough current and capacitors are used to supplement batteries. During off-peak working conditions, the capacitor is again recharged to a nominal voltage. Applications There are many applications which use capacitors as energy sources. They are used in audio equipment, uninterruptible power supplies, camera flashes, pulsed loads such as magnetic coils and lasers and so [… read more]

Electric Field

 
Electric Field

What is an electric field? An electric field is a special state that exists in the space surrounding an electrically charged particle. This special state affects all charged particles placed in the electric field. The true nature of electric fields, as well as the true nature of an electric charge is still unknown to scientists, but the effects of an electric field can be measured and predicted using known equations.  Just like a magnet creates an invisible magnetic field around it, which can be detected by placing a second magnet in its field and measuring the attractive or repulsive force acting on the magnets, electric charges create an electric field which can be detected by using a test charge. When a test charge is placed inside an electric field, an attractive or repulsive force acts upon it. This force is called the Coulomb force. In fact, magnetic and electric fields are not entirely separate phenomena. A magnetic field that changes with time creates – or “induces” an electric field, while a moving electric field induces a magnetic field as a direct consequence of the movement. Because these two fields are so tightly connected, the magnetic and electric fields are combined into one, unified, electromagnetic field. Electric field definition The electric field can be defined as a vector field which describes the relationship between the charge of a test particle introduced in the field and the force exerted upon this charged test particle.  Where E is the electric field, F is the force exerted on the test particle introduced into the field and q is the charge of the test particle. The unit for electric field is volts per meter [V·m-1] or newtons per coulomb [N·C-1]. The application of electric field in capacitors Electromagnetism is a science which studies static and [… read more]