snubber

A snubber is a device or circuit used to suppress transient voltages or currents in electrical and mechanical systems. In electronics, snubbers limit voltage spikes and dV/dt, protect switches such as transistors and IGBTs, and reduce electromagnetic interference and ringing across inductive loads like relays, transformers, and motors.

Electrical snubbers commonly take the form of RC networks connected across a switch or across the load. An RC snubber consists of a capacitor in series with a resistor; when the switch turns off, the energy stored in the inductance is partially transferred to the capacitor and dissipated in the resistor, limiting peak voltage and di/dt. An RCD snubber adds a diode to provide a fast current path and a clamp capacitor-resistor combo to absorb energy. For broader protection, clamping devices such as metal-oxide varistors (MOVs) or transient voltage suppression diodes (TVS) are used to cap the voltage. Design considerations include placement, component voltage and energy ratings, temperature effects, and aging.

Mechanical snubbers damp oscillations and shocks in machinery. They include dashpots (hydraulic or pneumatic), viscous dampers, or spring-damper arrangements. They are used to limit valve or actuator chatter, reduce pipe line hammer, and suppress vibrations in structures.

Snubbers are widely employed in power electronics, relays, motor drives, filter circuits, and other switching applications to improve reliability and reduce noise, wear, and EMI.