Many loudspeaker systems incorporate  PolySwitch devices for  overcurrent protection. By tripping  during high-current conditions and  resetting when no longer needed,  PolySwitch devices provide reliable  protection without the nuisance  and replacement costs  associated with fuses.  The Problem  Today’s speakers are generally  designed and sold independently  of amplifiers. Thus, mismatches  may occur, which can lead to damage.  Also, the advent of digital  recordings and compact discs  places extra burdens on sound  systems. Speaker damage can  result from a number of factors,  including the following situations: • High-power amplifiers used with  low-power speakers may simply  overdrive the speaker coils with  excessive power during sustained high volume. • Low-power amplifiers may be  overdriven so that clipping  occurs. This causes an upward  frequency shift of power...