In this tutorial we are going to learn about what is resistance and why used in circuit?

Resistance: It is use for the
opposition to current flow in an electrical circuit. The Resistance is measured
in ohms; resistance of symbol is omega (Ω), It is a German physicist which have
the relationship between voltage, current and resistance. It is generally depend on the formula
of the ohm’s Law.

All
materials resist current flow to some degree. They fall into one of two broad
categories:

- Conductors: Materials
which have very little resistance there electrons can move easily. Like that
– silver, copper, gold and aluminum.
- Insulators: Materials
which have high resistance and restrict the flow of electrons. Like that –
Rubber, paper, glass, wood and plastic.
- If have the higher the
resistance, then lower the current flow. If generally high, one possible cause
could be damaged conductors due to burning or corrosion.
- If in circuit have the lower
the resistance, the higher the current flow. Possible causes: insulators
damaged by moisture or overheating.
- Generally components, Like that heating elements and resistors, which
have a fixed-resistance value. Those values are often printed on the components’
in manuals for reference.
- If any tolerance is showing, then measured resistance value
should be within the given resistance range. If any significant change in a
fixed-resistance value usually indicates a problem.
- Resistance cannot be measured in running circuit. At the time of
troubleshooting technicians measured determine resistance by taking voltage and
current measurements and applying Ohm’s Law:
- E = I x R
- Here is, volts = amps x ohms. R stands for resistance in this
formula. While resistance is unknown, the formula can be converted to R = E/I
(ohms = volts divided by amps).Below are the taking example for resistance :
- In the first example, total normal circuit resistance, a known
reference value, is 50 Ω (250 ÷ 5 = 50 Ω). The 50 Ω resistances can help
determine the condition of a circuit.
- In the second example are taking, suppose that circuit current
is 3 amps instead of 4, then circuit resistance has increased from 50 Ω to 80 Ω
(250 ÷ 3 = 83.33 Ω).

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