brief introduction: Introduction:The DIAC is a diode that conducts electrical current only after its breakover voltage, VBO, has been reached momentarily. When breakdown occurs, the diode enters a region of negative dynamic resistance, leading to a decrease in the voltage drop across the diode and, usually, a sharp increase in current through the diode. The diode remains in conduction until the current through it drops below a value characteristic for the device, called the holding current, IH. Below this value, th