## Resistor

When an electric field is applied across a resistor, a limited current flows through it. In practical terms, doubling the electrical pressure results in a proportional doubling of current flow. The electric field distributes itself along and through the resistor, pushing charges over the resistive path. Ohm’s law governs the linear relationship between resistance (R), current (I), and voltage (V). It is expressed as I = V/R, where I is in amperes, V is in volts, and R is in ohms.

Resistance, measured in ohms, determines the limit of current flow for a given voltage. For instance, a 1-ohm resistor will restrict current to 1 ampere at 1 volt. Typical circuit resistors are often higher in value, such as a 1000-ohm resistor limiting current to 1 milliampere at 1 volt. Ohm’s law establishes the fundamental relationship that doubling voltage doubles current, while doubling resistance halves current, providing a crucial framework for understanding and designing electrical circuits.

### What is a Carbon Resistor?

A carbon resistor is a controlled limited conductor in electrical circuits, functioning as a flow restrictor for electric current. Analogous to a water hose connected to a cylinder filled with packed sand, the flow of water through the cylinder depends on factors like its length, cross-sectional area, grain size, and water pressure. In the electrical realm, this flow restrictor corresponds to a resistor.

Constructed from a mixture of powdered carbon and a nonconductive plastic filler, a carbon resistor’s resistance is controlled by adjusting the ratio of filler to carbon. This mixture is compressed and fused under pressure to create the resistive element. Encased in an inert housing marked with a color code, the resistor features conductive leads connecting to the resistive element at both ends. The electrical symbol for a resistor is denoted by the capital letter R.