What happens when the gate level on an SCR drops below the trigger point while anode and cathode voltages are maintained?

When the gate level on a silicon-controlled rectifier (SCR) drops below the trigger point while the anode and cathode voltages are maintained, the SCR remains on. This behavior is due to the nature of how SCRs operate. Once the SCR is triggered into conduction by a gate signal, it continues to conduct even if the gate current is removed, as long as there is sufficient anode current to keep it in the on state. This means that as long as the anode-to-cathode voltage is maintained above the holding current level, the SCR will remain in the conducting state.

The SCR will only turn off when the current flowing through it drops below a certain threshold, known as the holding current. Therefore, in this scenario, with the gate voltage falling below the trigger point but the anode and cathode voltages sustained, the SCR will indeed stay on as long as the conditions allow for current to continue flowing through it.