DB3, DB4, SMDB3 DIAC DiodesST Microelectronics Functioning as a trigger diode with a fixed voltage reference, the DB3/DB4 series can be used in conjunction with triacs for simplified gate control circuits or as a starting element in fluorescent lamp ballasts.The surface mount SOT23-3L package allows compact, SMD based designs for automated manufacturing.Features and BenefitsVBO: 32 V and 40 VLow breakover currentBreakover voltage symmetry: 3VECOPACK®2 compliantApplicationsTriggering device for Triac or SCR based motor/ light dimmer32 V trigger device for oscillator circuitStart-up triggering in lighting ballast for CFL, TL or LED lampsThe DIAC, or 'diode for alternating current', is a diode that conducts current only after its breakover voltage has been reached momentarily.