Need help verifying a schematic diagram

Discussion in 'The Projects Forum' started by dello, Mar 4, 2009.

  1. dello

    Thread Starter New Member

    Mar 4, 2009
    I have a schematic diagram here.. i was wondering if some of the experienced guys over here could help me verify if this circuit would work if i were to build it. Its a rather simple circuit, here is the part list for the circuit and also the diagram... hope someone could give me some comments... thanks alot

    C1 10nF ceramic disc capacitor

    C2 100nF ceramic disc capacitor

    C3 1000uF electrolytic capacitor

    D1 1N4148 signal diode

    D2 LED

    Q1 BC327 TO-92 transistor

    R1 10K 0.25W variable resistor

    R2 1K 0.25W variable resistor

    R3, R4 470R 0.5W resistor

    U1 TL072 Op-amp


    This circuit basically consists of P1 and P2 which are measurement rods driven into soil.. and a voltage will be indicated at the voltmeter attached at P3 and P4, potentiometer R1 is to adjust the range of the voltage so that it will be between the 15 v voltmeter. The op amp basically compares the value.. R2 is adjusted till the motor starts ( motor outputs are P6 and P5) the transistor amplifies the current to the motor, while the diode avoids the circuit from getting burnt from the motors inductance while the capacitors help smoother the circuits output
  2. Bernard


    Aug 7, 2008
    Should work, soil dries out, small motor comes on.