# What happens if a wire has high resistance?

The lower the current flow, the greater the resistance. If the voltage is very high, one probable explanation (among many) might be burned or corroded wires. Because all conductors emit some degree of heat, overheating is a problem that is frequently related with resistance. The higher the temperature, the more likely it is to break down insulation and cause a short circuit.

The best way to check for open circuits is with a volt-ohm meter. If there is no power at all on any line, the meter will show an open circuit.

If you find that one or more lines are bad, the first thing to do is not touch them with your hands! Use a non-metallic tool to test each conductor individually. If one channel of the meter shows a closed circuit while the other opens, then that means at least one of the wires is okay.

If after checking all the cables you're still not sure, get help from an electrician. There could be a damaged panel inside the house, or even a downed power line outside the property line.

## What does it mean if something has high resistance?

Resistance measurements are often used to determine the state of a component or a circuit. If there is no voltage at all, then something is definitely wrong.

High resistance means that you or something else can't make the circuit work. For example: A wire is "high-resi...

## What happens to the resistance of a wire if it is heated?

The ions bounce more fiercely as the wire heats up. This makes electrons move more slowly down the wire. As a result, resistance is growing. When the wire gets hot enough, all the ions and electrons are moving together, so resistance becomes zero. The wire is now "cold" again.

## Why should a cable have low resistance?

In most applications, reduced resistance implies that less power is converted to heat and lost to the environment, and that more of the given power reaches its intended destination. It also implies that the wire and cable will run cooler, and that the power source can be smaller for a given load. The resistance of a conductor such as copper decreases with its diameter, so larger cables use less resistive material than do smaller ones. Tubes are even better conductors than wires, so fiber-optic communications cables tend to be very thin--usually no thicker than their equivalent wire cable.

Resistance is a measure of how much energy it takes to move an electric charge through a conductor. The resistance varies depending on what kind of conductor you are talking about, but for simplicity's sake, we can say that resistance is the force that needs to be applied to a current to cause it to flow. For example, the resistance of a copper wire is about 1 ohm; if we need to drive a one-ampere current through the wire, we will have to apply a voltage of one volt across it.

The higher the resistance, the more power is lost as heat. So, all other things being equal, cables with lower resistance lose less power and are therefore safer to operate. They also require less electricity from your battery or generator to work.

There are many different materials used in cable construction.

## What does the high internal resistance prevent?

What does a high level of internal resistance prevent? High resistance, limited current, voltage dips when loaded, and the battery warms up. Internal battery resistance effects on Figure 1: A low-internal-resistance battery provides high current on demand. The battery's capacity is reduced over time as it loses charge. As it approaches empty, its ability to deliver current decreases until it can no longer supply any power to the load.

Batteries have two types of resistance: short circuit and open circuit. In short circuit tests, the technician attaches a test light or other source of current to the battery terminals in order to determine how far they can be separated before the connection breaks. The amount of current that can be delivered with no break is called the battery's discharge rate. Batteries must be tested when new and then periodically rechecked during use to ensure they are still delivering enough current for their application. Excessive discharge will quickly reduce the capacity of most batteries to below acceptable levels.

Internal resistance prevents the flow of current between the positive and negative electrodes within the cell. As long as there is some remaining capacity in the battery, it will continue to provide current even if no one is using it. This property allows batteries to keep equipment powered up while it is being repaired or replaced. However, if the resistance becomes too high, current will be limited to avoid damaging the battery.

##### Roger Amaral

Roger Amaral is the kind of person who will stop and ask if he can help you with something. He's very knowledgable about all kinds of things, from electronics to history to geography to religion. He loves learning new things, and is always looking for ways to improve himself.

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