Handbook 652 Body Electrical Diagnosis Resistance Some materials allow current to flow through them easily. Other materials do not. Electrical resistance describes how much a material opposes current flow. This opposition to current is measured in Ohms (Ω) or in kilohms (kΩ). One kΩ equals 1,000 Ohms. In every circuit resistance Resistance determines the amount of current flow as long as the voltage stays constant. Materials with very low resistance are called conductors . Copper, aluminum, gold, and silver are good conductors. Materials with extremely high resistance are called insulators . Rubber, glass, paper, ceramics, plastics and air are good insulators.
Materials that are neither good conductors nor good insulators are called semiconductors . Silicon is an example of a semiconductor. In a “ perfect ” circuit, the only resistance would be the load you are operating with the circuit. But even the best conductors have a certain amount of electrical resistance. Resistance is measured using an ohmmeter. Technical Training 29