Snubber Circuits

A MORE PRACTICAL TURN-ON SNUBBER
As with the turn-off snubber, the turn-on snubber requires additional
components to allow the transistor to survive. In this case, if nothing
were added to the circuit, the transistor would recieve an impulse of
voltage when it turned off, because the inductor current would be
forced to change in a very short time. To avoid this potentially
destructive transient, a resistor and a diode can be added to the
snubber circuit, as shown above.The resistor R s provides an alternative
path for the inductor current when the transistor turns off. The purpose
of the D s is to keep the resistor from conducting during the turn-on
transition