What is the effect of adding a resistor in a digital circuit?

Adding a resistor in a digital circuit primarily serves to limit current flow. This is crucial because digital circuits often operate at specific voltage levels, and excessive current can lead to overheating components, potential damage, or incorrect functioning of the circuit. By incorporating a resistor, you ensure that the current stays within acceptable limits, protecting sensitive components and maintaining overall circuit stability.

Resistors are used in various applications like current limiting for LEDs, pull-up or pull-down configurations for logic inputs, and to manage voltages at specific nodes in the circuit. The value of the resistor determines how much current will flow, thus playing a critical role in circuit design and safety.