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).