Sunday 1 July 2012

Resistance and Ohm's Law


                   The electrical resistance of a circuit component or device is defined as the ratio of the voltage applied to the electric current which flows through it. It is a property of a component to oppose the passage of electric current. Resistors are devices which provide resistance in a circuit. Resistance, together with current and voltage, compose the Ohm’s law which shows the relationship between them. When the resistance of a material remains constant in a wide range of voltage then the material is said to be an ohmic material.
the power supply
readings
                  In this experiment, there are a number of set-ups made to study the nature of resistors and its types. Carbon film resistors, metal film resistors, ceramic resistors, resistance box and a rheostat were individually examined of their properties and function. Studies of a combination of resistors were done as well for a full grasp of the nature of resistors. The group recorded the resistance values of each device and how it affected the current when variable voltage is applied to the circuit. In doing this, sufficient information about resistors was gathered.
resistance box
          It was found out that the values of the color coded ceramic resistors are close to their actual resistance, the resistance box is a series of resistors with different strengths of opposition to current, the rheostat supplies a wide range of resistance along its length, a combination of resistors has a variable total resistance depending on the orientation of the circuit and that the electric current and voltage is directly proportional under constant resistance. 
breadboard


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