Application Specific Snubber Resistor

In electronic systems it is important to control voltage transients to prevent damage to electronic components. Snubber circuits manufactured using a power resistor and capacitor are one solution.

In electronic systems voltage spikes are generated by circuit inductance when a switch (mechanical or semiconductor) is opened. These voltage spikes (ringing) can damage electronic components and must be damped or eliminated. A RC snubber circuit constructed using a power resistor in series with a capacitor connected across the switch is a common solution.

Snubber Resistor Applications

A snubber circuit provides an alternative path for the current flowing through a circuit intrinsic leakage inductance and:

  • Eliminates (or reduces) voltage or current spikes.
  • Reduces losses due to switching.
  • Reduces electromagnetic interference with other electronic equipment by reducing the ringing component.
  • Transfers power dissipation to a power resistor and away from the switch.
  • Shapes the load and keeps it within a safe operating area.

A power resistor manufactured using thick film technology is an ideal choice as it can dissipate a large amount of power from a small physical area and it is low inductance. Carbon film resistors may also be used but wirewound resistors are not applicable due to their relatively high inductance.

Snubber Resistor Design

Snubber circuit design involves compromises including 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 a application can compromise the capacitor choice 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 snubber resistor. Contact us today on 01207 230728