Category Archives: Electronics

Resistance Colour Coding calculation


Example:       Circuit symbol:   


Resistors restrict the flow of electric current, for example a resistor is placed in series with a light-emitting diode (LED) to limit the current passing through the LED.

Connecting and soldering

Continue reading Resistance Colour Coding calculation

Resistivity Calculation

Resistivity Calculation – The electrical resistance of a wire would be expected to be greater for a longer wire, less for a wire of larger cross sectional area, and would be expected to depend upon the material out of which the wire is made (resistivity). Experimentally, the dependence upon these properties is a straightforward one for a wide range of conditions, and the resistance of a wire can be expressed as

Continue reading Resistivity Calculation

Resistance and Conductance

Resistance and Conductance


The electrical resistance of a circuit component or device is defined as the ratio of the voltage applied to the electric current whichflows through it:


If the resistance is constant over a considerable range of voltage, then Ohm's law,

I = V/R, can be used to predict the behavior of the material. Although the definition above involves DC current and voltage, the same definition holds for the AC application of resistors.

Continue reading Resistance and Conductance