Resistance is the measure of opposition to the flow of current in a circuit. It is measured in Ohms (Ω) and is represented by the symbol R.
According to Ohm's Law, resistance is directly proportional to voltage and inversely proportional to current. This means that as resistance increases, current decreases, and as resistance decreases, current increases. Voltage remains constant.
Resistance is affected by the physical properties of a material, such as its length, cross-sectional area, and temperature. It is also influenced by the type of material and its composition.
The formula for calculating resistance is R = V/I, where R is resistance in Ohms, V is voltage in volts, and I is current in amperes. This formula can also be rearranged to calculate voltage or current when the other two values are known.
Resistance and impedance are similar in that they both measure opposition to current flow, but they are not the same. Resistance is the opposition to direct current (DC) flow, while impedance is the opposition to alternating current (AC) flow. Impedance takes into account both resistance and reactance (the opposition to AC flow caused by capacitance and inductance).