In Vol. III of Semiconductors in the Thryistors section, it discusses the use of a rectifier diode to be placed before the gate of a silicon controlled rectifier when the SCR has a gate-cathode resistor. Other than preventing reverse flow of current through the noted gate-cathode resistor, what other purpose does this protection diode perform? Does it prevent damage to the gate junction itself via reverse voltage/current, or is it simply to stop reverse flow through the gate for other reasons not noted? I have used both sensitive gate SCR's and SCR's with a gate-cathode resistor, and I am having trouble finding information about my question noted above. Can anyone help me out on this one?
Thanks!
Thanks!