The ETB-266 Diode, Zener Diode & LED Characteristics Trainer is an educational platform designed for the study of V-I characteristics of semiconductor diodes. This includes PN junction diodes, Zener diodes, and Light Emitting Diodes (LEDs). The setup allows students to analyze forward and reverse bias behavior, breakdown voltage in Zener diodes, and LED conduction with luminosity response. Equipped with a built-in power supply and measuring instruments, this model is ideal for basic electronics and semiconductor theory labs.