An ohm is unit of electrical resistance between two conductors. Resistance directly affects the output of the charger. Generally, the relationship is negative. Higher resistance(ohms) means less power output by the charger. The higher the resistance of your fence, the weaker the shock to the animal. This can be plotted on a chart, but we've taken it a step further, and directly plot the output to the animal (the animal has an ohm rating as well). What effects the resistance of my fence? Your Electric Fence Wire - There are many different types of wire one can use to wire their electric fence. However, not all wire is created equal. Some types of wire have a higher resistance than other wires, that is they have a higher omhs per mile rating. We suggest using 12 1/2 Gauge or 14 Gauge wire on your electric fence. Consider the difference between 12 1/2 gauge wire resist at 56 ohms/mile, and Gallagher Equifence Conductive Wire which resist at 560 ohms/mile. The gallagher wire is 10 TIMES more resistant to electric currents. Play with the calculator at the top of the page - select a good wire, and then a high resistance wire. Notice the drop in power to the animal! Length of Your Fence - Remember, fence wire resists a certain number of ohms per mile. The longer your fence, the more that resistance adds up. However, you can still fence large areas successfully if you use a good wire. Example. A 5 mile fence using 12 1/2 gauge wire is only 280 ohms. A 2 mile fence using Gallagher Equifence Conductive Wire resist at 1120 ohms! You would deliver more shock to the cow at the end of the 5 mile fence than the 2 mile fence. The Animal - Animals (you included) resist an electrical current. This means animals have an ohm rating. For simpliticy sake, we figure a good sized cow at 100 ohms. Larger animals resist electrical current more than smaller animals. Your charger will deliver more power to a smaller animal than a larger one because of this. Jumpers - Jumpers are an easy to implement, inexpensive way to drastically lower the resistance on your fence - this will allow your charger to hit harder. Remember, resistance zaps the power from your electric fence charger. Jumpers are used at the corner post of your fence to 'jump' the power from wire to wire. This effect us most pronounced on longer fences, or if poor quality wire is used. Matter of fact, if you have an existing fence with poor quality wire, using jumpers can cheaply and quickly increase the shock to the animal. Be sure to check the option above you will be amazed at the difference this quick fix will make.