Computer engineering..

Voltage across SCR1 is Vbm = 1. Voltage across (n-1)SCR is (n-1) 12R, so the voltage equation for the series circuit is VS,R+ (-1)/PUR (-) As-1- zal - Sen Vy - - - - I - The V-R-) Vs-V-RI-RAR Ri. SAV.hu - Vhon SO -VINA - - if SCR data sheet sally contain only maximum blocking current.bmx so we assume Imeno So Abmx So the value of R calculated is low than actually required. SCRS having characteristics: unequal dynamic It may occur that SCRS may have unequal dynamic characteristics so the voltage distribution across the SCR may be unequal during the transient condition. me state can be achieved by connect a suitable resistance across each SCRs, so that parallel combination have same resistance, But this is a cumbersome work. During steady state operation we connect same value of shunt resistance across each SCRs. This shunt resistance is called state equalizing circuit. Suppose, Art a Che three Current m - -1 iwwe I TI he sing we Statie velge utfordre Let SCR1 has lower leakage current I , It will block a voltage comparatively larger than other SCRs. Voltage across SCR1 is Vbm = 1. Voltage across (n-1)SCR is (n-1) 12R, so the voltage vos 14) b) -VIVOVI Significance of string efficiency. Two SCRs are have same forward blocking voltage , When system voltage is more then the voltage rating of a single SCR. SCRs are connected in series in a string. There is a inherent variation in characteristics. So voltage shared by each SCR may not be equal. Suppose, SCR1 leakage resistance > SCR2 leakage resistance for same leakage current lo in the series connected SCRs. For same leakage current SCR1 supports a voltage V1, SCR supports a voltage V2. 22 So string oy for two SCRS - - 1 + V. The above operation is when SCRs are So. WWWVwLWxri ciceceli