The 100 K ohm variable resistor is where the cadmium sulfide LDR (1 K in full light and 100 K in total darkness) should be connected. The 8 ohm resistor is where the miniature polarized audio transducer connects. Transistors are 2N2907 and 2N2222.
This light to sound circuit helps blind or visually impaired to locate windows, doors, or lights others have left on. The audio pitch (frequency) varies with light changes on LDR.
Circuit changes to consider is LDR is traded for Thermistor or humidity sensor to change frequency.
