Draw the schematic symbol of the SCR, UJT, Diac, Triac, and IGBT. Explain the characteristics and the operation of SCRs, UJTs, Diacs, Triacs, and IGBTs. Draw the current–voltage characteristic curve for an SCR, a UJT, a Diac, and a Triac. Describe ways in which voltages at the leads of SCRs, UJTs, Diacs, Triacs, and IGBTs turn them on and off. Draw the waveforms produced at the output of SCRs, UJTs, Diacs, and Triacs when various voltages are applied to their inputs. Describe the operation of various sample circuits that have SCRs, UJTs, Diacs, and Triacs.