_______________________________________________________________________ Special Devices
Figure 3-18. SCR Structure
3-42. Figure 3-19 shows the characteristic curve for the SCR. With no gate current, the
leakage current remains very small as the forward voltage from cathode to anode is
increased until the breakdown point is reached. Here the center junction breaks down, the
SCR begins to conduct heavily, and the drop across the SCR becomes very low.
Figure 3-19. Characteristic Curve for an SCR
3-43. Figure 3-20 shows the effect of a gate signal on the firing of an SCR. Breakdown
of the center junction can be achieved at speeds approaching a microsecond by applying an
appropriate signal to the gate lead, while holding the anode voltage constant. After
23 June 2005
TC 9-62
3-13
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