This unit is to Study of Photo Diode characteristics (continuously variable) @ 50 mA on the panel. with socket for easy connection. the photodiode. out at banana sockets for flexibility. sturdy, and easy-to-operate design. Instrument comprises of DC Regulated Power Supply 03 VDC/150mA, two round meters for voltage & current measurement, LDR, Photo Transistor, Photo Diode & LED mounted in a metal box, connections of Supplies, meters & components are brought out at 4mm Sockets.