Circuit RC Snubber
Due to over heating, over
voltage, over current or excessive change in voltage or current switching devices and circuit components may fail.
From over current they can be protected by placing fuses at suitable locations. Heat sinks and fans can be used to take the excess heat away from switching devices and other components.
Snubber
circuits are needed to limit the rate of change in voltage or current (di/dt or dv/dt) and over voltage during turn-on and turn-off. Static dv/dt is a measure of the ability of a thyristor to retain a blocking state under the influence of a voltage transient.
It is important that R in the RC snubber, have low self inductance. Inductance in R will increase the peak voltage and it will tend to defeat the purpose of the snubber.
Low inductance will also be desirable for R in snubber but it is not critical since the effect of a small amount of inductance is to slightly increase the reset time of C and it will reduce the peak current in switch at turn-on. The normal choice of R is usually the carbon composition or metal film.
When comparing the Quick design to optimum design, the required snubber resistor’s power capability will be reduced. Usually the “Quick” design is completely adequate for final design. Going to the “Optimum” approach is only if power efficiency and size constraints dictate the need for optimum design.