# 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.