Thyristor Turn ON Methods 
·         Thermal Turn on: If the temperature of the thyristor is high, there will be an increase in charge carriers which would increase the leakage current. This type of turn on many causes thermal run away and is usually avoided.
·         Light: If light be allowed to fall on the junctions of a thyristor, charge carrier concentration would increase which may turn on the SCR.
·         LASCR: Light activated SCRs are turned on by allowing light to strike the silicon wafer.
·         High Voltage Triggering: This is triggering without application of gate voltage with only application of a large voltage across the anode-cathode such that it is greater than the forward breakdown voltage VBO. This type of turn on is destructive and should be avoided.
·         Gate Triggering: Gate triggering is the method practically employed to turn-on the thyristor. Gate triggering will be discussed in detail later.
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Triggering: Under transient conditions, the capacitances of the p-n junction will influence the characteristics of a thyristor. If the thyristor is in the blocking state, a rapidly rising voltage applied across the device would cause a high current to flow through the device resulting in turn-on.
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