# Resistance Summary

In our resistance abstract, we collect and compile the resistance information we have seen so far.

• The task of resistance is to limit the current passing through an electrical circuit.
• Resistance is measured in Ohm and indicated by the symbol Ω.
• Carbon, Film and Wirewound (stone) are all kinds of different resistance.
• Resistance color codes are used to determine the resistance and degree of tolerance of small resistors.
• The BS1852 Standard uses letters and is used to describe large-sized resistors.
• Tolerance is a percentage measure of the accuracy of a resistance from its preferred value with the tolerance values E6 (20%), E12 (10%), E24 (5%) and E96 (%1).'

## SerialLy Connected Resistors

• It is said that the resistors that are chained together in a single line are connected as SERIES.
• There is a common current passing through the serially connected resistors.
• I total = I 1 = I 2 = I 3 ….
• The total circuit resistance of serial resistors is equal to:
• R total = R 1 + R 2 + R 3 + ….. R n, etc.
• The total circuit voltage is equal to the sum of all individual voltage drops.
• V total = V 1 + V 2 + V 3 ….
• The total resistance of a series-connected circuit will always be greater than the highest value resistance.

## Parallel Connected Resistors

• Both terminals are said to be connected in PARALLEL to the resistors connected to each terminal of another resistance or resistance.
• Parallel resistors have a common Voltage between them.
• V S = V 1 = V 2 = V 3 ….
• The total resistance of the parallel circuit is equal to:
• The total circuit current flow is equal to the sum of all individual branch currents added together.
• I total = I 1 + I 2 + I 3
• The total resistance of a parallel circuit will always be smaller than the value of the smallest resistance.

## Resistance Power Rating

• The larger the power rating, the greater the physical size of the resistance to dissipate heat.
• All resistors have a maximum power rating, and if exceeded, it causes the resistance to overheat and damage.
• Standard resistance strength rating sizes are 1/8 W, 1/4 W, 1/2 W, 1 W and 2 W.
• Low omic value power resistors are often used for current detection or power supply applications.
• The power rating of resistors can be calculated using the following formula:
• In AC Circuits, the voltage and current flowing in a pure resistance is always "intra-phase ", which produces 0 o phase shifts.
• When used in AC Circuits, the AC impedance of a resistance is equal to DC Resistance.
• Ac circuit impedance for resistors is given with the symbol Z.