A botanical laboratory requires an op.amp. alarm circuit which will indicate when the soil in a plant pot is not moist enough. With the assistance of the in information below design such a circuit remembering to include suitable values for any resistors used. when two copper probe wires are inserted into the soil 15cm and the soil is wet, the resistancw between them is 1.3kohms. However as the soil dries out the resistance increases and reaches a value of 85kohms when the soil is too dry. All i know is to use a wheatstone bridge. from here i am lost can someone please help.