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Renesas Electronics America - Knowledgebase

What are the causes if thyristor is on without a gate trigger signal?

Latest Updated:04/01/2008


A thyristor may switch on even without a gate trigger signal.
What are the possible causes?


Have you taken any action against false firing due to dVD/dt?
If not, insert the following resistance and capacitance, as shown in the figure below, to prevent false firing.

Between gate (G) and cathode (K)     R: 1 kΩ, C: 0.01 to 0.1 uF
Between anode (A) and cathode (K)    R: 100 Ω, C: 0.022 to 0.1 uF

Decide the values of C and R, taking the operating temperature range and noise environment into consideration.

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