 ## What is a specific resistance?

Specific resistance is defined as the resistance offered per unit length and unit cross-sectional area when a known amount of voltage is applied..

## Is voltage directly proportional to resistance?

In other words, the current is directly proportional to the voltage and inversely proportional to the resistance. So, an increase in the voltage will increase the current as long as the resistance is held constant. … If the current is held constant, an increase in voltage will result in an increase in resistance.

## What happens to resistance when current increases?

The relationship between resistance and the area of the cross section of a wire is inversely proportional . When resistance is increased in a circuit , for example by adding more electrical components , the current decreases as a result.

## Can current flow without resistance?

Superconductivity, by definition, is a current flowing without resistance. This is only possible if the voltage across the junction is 0, otherwise there would necessarily be both current and voltage and therefore an effective resistance R=V/I.

## Do LEDs have resistance?

The long answer: LEDs are semiconductors, diodes in particular. … Current versus voltage is a straight line for a resistor, but not at all for an LED. Because of this, you can’t say that LEDs have “resistance.” Resistance is defined as the constant ratio of voltage to current in a resistive circuit element.

## Does higher resistance mean higher voltage?

In electrical terms, this is represented by two circuits with equal voltages and different resistances. The circuit with the higher resistance will allow less charge to flow, meaning the circuit with higher resistance has less current flowing through it.

## Does resistance cause voltage?

As electrons pass through a resistance, they lose energy as they interact with electrons in the conducting material. As energy is given up to the material, it gains thermal energy so its temperature rises. The moving electrons lose potential energy and hence there is a drop in voltage.

## How do I reduce 5v to 1.5 V?

In voltage divider circuit you want to drop 3.8V across R1 to get Vout = 1.5V. This can be done by n number of combinations of R1 & R2 values. For e.g. you can use R1=3.8K and R2=1.2K or R1=3.8Ω and R2= 1.2Ω.

## What resistor do I need to drop 12v to 5v?

PLace two resistors in series with the 2nd resistor value (5/7) of the first resistor value. Place the resistors between 12v and ground and then you will get 5v at the point between them. This is a very crude way of doing it. It is unregulated so the voltage out will be dependent of voltage in.

## What causes voltage to increase?

The main cause of these voltage surges in power system are due to lightning impulses and switching impulses of the system. But over voltage in the power system may also be caused by, insulation failure, arcing ground and resonance etc. … But over voltages occur in the power system due to lightning is very high.

## How does increasing resistance affect voltage?

Ohm’s law states that the electrical current (I) flowing in an circuit is proportional to the voltage (V) and inversely proportional to the resistance (R). … Similarly, increasing the resistance of the circuit will lower the current flow if the voltage is not changed.

## Does high resistance cause voltage drop?

Causes of Voltage Drop Excessive dropping is due to increased resistance in a circuit, typically caused by an increased load, or energy used to power electric lights, in the form of extra connections, components, or high-resistance conductors.

## What happens to resistance when length is doubled?

The resistance of a conductor is directly proportional to its length (L) as R ∝ L. Thus doubling its length will double its resistance, while halving its length would halve its resistance.

## Why does resistance decrease voltage?

If the resistor is in series with some other element, and they together are powered by a constant voltage source, then the voltage dropped across the resistor means there’s less voltage available for the other circuit element. It doesn’t mean that the voltage of the source decreased.

## Does Resistance reduce voltage?

Absolutely! A resistor is about to reduce the current and voltage. For example, when the current flows through the resistor, it will always generate a voltage drop, and which is mainly reflected in the decrease of the output current and the voltage.

## Does more current mean more resistance?

In electrical terms, this is represented by two circuits with equal voltages and different resistances. … The circuit with the higher resistance will allow less charge to flow, meaning the circuit with higher resistance has less current flowing through it.