How it works
A resistor opposes the flow of electric current. The relationship between voltage, current, and resistance follows Ohm's Law: V = I × R. The higher the resistance in ohms (Ω), the less current flows for a given voltage.
Resistors are used to limit current to protect other components (like an LED), to divide voltage between two points, or to set bias points in transistor circuits. Real resistors are also rated for power dissipation (commonly 1/8W, 1/4W, 1/2W, 1W) — exceeding this rating causes the resistor to overheat and fail.
Fixed resistors have a color-coded value that doesn't change. A potentiometer is the variable version of a resistor, and both use the same underlying physics in CircuitForge's solver.