What type of device helps protect against electromagnetic interference (EMI)?

The correct answer is EMI filters, which are specifically designed to mitigate the effects of electromagnetic interference (EMI) on electronic devices and systems. EMI filters work by allowing the desired signals to pass through while blocking unwanted electromagnetic noise or signals that can disrupt the operation of sensitive electronic components. They achieve this through the use of inductors, capacitors, and resistors, which can effectively attenuate undesired frequencies. By incorporating these filters, devices can ensure better performance and reliability in environments where EMI is present, such as industrial settings or areas with a high density of electronic equipment.

Other devices listed, such as voltage stabilizers, surge protectors, and capacitors, serve distinct functions. Voltage stabilizers manage fluctuations in voltage, surge protectors primarily guard against voltage spikes caused by surges or transients, and capacitors can store and release electrical energy but are not specifically aimed at EMI reduction. While they can contribute in varied contexts, they do not directly address EMI issues like EMI filters do.