Application Specific Snubber Resistor

In electronic systems voltage spikes are generated by circuit inductance when a switch (mechanical or semiconductor) is opened.It is important to damp or eliminate these transient conditions to prevent damage to sensitive electronic components. Snubber circuits manufactured using a snubber resistor and capacitor are a common solution.

These voltage spikes (ringing) can damage electronic components and must be damped or eliminated. is a common solution.


Snubber Resistor Applications


A RC snubber circuit constructed using a power resistor in series with a capacitor connected across the switch provides an alternative path for the current flowing through a circuit intrinsic leakage inductance. A correctly designed snubber circuit can:


  • Eliminate (or reduce) voltage or current spikes.

  • Reduce losses due to switching.

  • Reduce electromagnetic interference with other electronic equipment by reducing the ringing component.

  • Transfer power dissipation to a power resistor and away from the switch.

  • Shape the load and keeps it within a safe operating area.

Wirewound power resistors are generally not suitable for snubber resistor applications due to their relatively high inductance. Carbon film or thick film resistor technology tends to be used in snubber resistor applications. Thick film resistor technology is often used due to its power handling capabilities in a relatively small unit area, its low inductance and its relatively low cost.

Snubber Resistor Design


Snubber circuit design involves compromises between voltage rate, peak voltage, turn off time and component cost. In some cases, paper design is not sufficient and experimentation is required to achieve the optimum result. Choosing the perfect power resistor for an application can compromise the choice of capacitor and visa versa.


Although simple in principle snubber circuits manufactured using a power resistor and capacitor present a number of design challenges. If designed incorrectly the circuit will fail to control voltage transients appropriately which could result in damage to sensitive electronic circuits and system failure. TSEC Engineers are always available to assist in snubber circuit designs working with you to ensure the correct choice of application specific snubber resistor. Contact us today on 01207 230728