Snubbers

A snubber is a device or circuit designed to suppress or damp transient phenomena in electrical or mechanical systems. In electronics, snubbers limit voltage or current spikes that occur when inductive loads are switched off, reducing electromagnetic interference and protecting switching devices such as diodes, transistors, and thyristors.

Electrical snubbers come in several common forms. RC snubbers place a resistor and capacitor in series across a switch or an inductive load to absorb energy and limit overvoltage. Diode snubbers, or flyback diodes, provide a path for inductive current when a switch opens. RCD snubbers combine resistor, capacitor, and diode to absorb energy efficiently and safely. Zener or transient voltage suppressor (TVS) snubbers clamp the voltage to a safe level. Snubbers can be passive (RC, RCD) or active, using additional circuitry to shape the response.

In mechanical contexts, snubbers dampen motion or absorb shocks to prevent damage from oscillations, often serving as dampers or buffers in valves, actuators, and piping systems. Hydraulic, pneumatic, or spring-damper assemblies are common, and snubbers help control impacts and limit travel.

Design considerations include the amount of energy to be dissipated, peak voltage or force limits, leakage currents, temperature, and servicing needs. Snubber selection depends on the duty cycle of the operating circuit and the energy stored in inductive loads, often estimated by E = 1/2 L I^2.

Applications span power supplies, motor drives, relays and contactors, switching power converters, automotive electronics, and industrial controls, as well as piping systems prone to water hammer. The overarching purpose is controlled energy dissipation to protect components and reduce transient effects.