Turn on uniformity of two multi finger silicon controlled rectifiers (SCRs) with different combinations of anode/cathode regions are studied using the transmission line pulsing (TLP) tester The finger turn on mechanisms of these devices are explained from the current flow path and equivalent circuit views The dV/dt effect of pulses with different rise times on the finger turn on behavior of the SCRs are also investigated experimentally (C) 2010 Elsevier Ltd All rights reserved