TO STUDY FORWARD & REVERSE CHARACTERISTICS OF PN JUNCTION DIODE. INSTRUMENT COMPRISES OF TWO DC REGULATED POWER SUPPLIES 0-3VDC/150MA & 0-30 VDC/150MA, TWO DUAL RANGE ROUND METERS FOR VOLTAGE & CURRENT MEASUREMENT, PN JUNCTION DIODES MOUNTED BEHIND THE PANEL, CONNECTIONS OF SUPPLIES, METERS & DIODES BROUGHT OUT AT 4 MM SOCKETS.