5 March 2018

Compare SCR and Asymmetrical SCR ( ASCR )


Asymmetrical SCR
  • The reverse blocking capacity of the ASCR is very low. 
  • It is in the order of 20  to 30 V. 
  • The ASCR is useful where very low reverse blocking capacity requires.
  • The forward blocking capacity of the ASCR is very high typically 400 to 2000 V. 
  • The forward and reverse blocking capacity of the ASCR are not equal.
  • There is additional N2+ layer added in the ASCR therefore N2  become narrow. 
  • The N2+ layer is acts as Electrical field stopper. The P2N2+ junction avalanches at very low voltage therefore the ASCR does any usable peak repetitive voltage rating ( VRRM ).  
  • The ASCR has faster turn off time and reduction in ON state voltage is achieved by sacrificing reverse voltage blocking capacity.
  • If the gold doping is same as that of conventional SCR, the on state voltage drop is reduced but turn off time is unaltered. 
  • It should be noted that the on state voltage drop and turn off time of the ASCR is adjusted by suitable doping level of N2 .


compare scr and asymmetrical scr

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