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    • #8554
      LectronFan
      Moderator

        Hi all,

        I hope you enjoyed the circuit of yesterday and that you didn’t take the circuit apart yet.

        Today, we are going to add a few components to turn the motor on or off by using 2 switches.

        If we press S1 and turn the motor shaft, it will start spinning.

        And as we mentioned before that we should take care of our motor and battery, the motor turns itself off after a little time. We can also stop the motor by pressing S2.

        If you look at the diagram, you notice that we use a capacitor with only a relatively small capacitor of 0,47 µF.

        This capacitor is charged by pressing S1. Since our Darlington transistor pair is very sensitive and our Mosfet has a very high input resitance, the capacitor discharges at a very slow rate.

        Of course, when we press S2, the capacitor suddenly discharges making the motor stop.

        Mosfet transistors are mostly used in switching aplications (like a switching mode power supply, relay drivers, etc.)

        The Mosfets in our Lectron set incorporate also a zener diode across Drain and Source. This diode protects the Mosfet against power supply spikes, reversed currents and overvoltages.

        Here’s the circuit :

        Motor switch

      • #8564
        Michael
        Keymaster

          Hi  Frank,

          Thanks very much for taking us on a new journey with the motor and magnet set you recently received.  Very good exploration that was not in the original learning manual prepared by Herr Kopperschmidt.  Thanks so much, M.

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