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    • #8561

        Hi all,

        How about combining the Lectron motor with the HEX display ?

        Well, here’s a simple circuit that shows the principle.

        It’s based on previous experiment where we studied the behaviour of the electromagnetic fields.

        Can you see a difference in the way the motor is connected ?

        Each time we turn the motor shaft, a small voltage is induced in the motor coil. This voltage is applied to the Base of T1.

        The transistor is so biased, that the collector voltage in motor rest is about 1 Volts.

        The output of the transistor amplifier is connected to the Lectron counter. The counter sees this 1V as LOW.

        When the motor shaft is turned, the small voltages are amplified and appear at the collector rising up to 6V.

        The counter sees them as a HIGH, thus the counting starts.

        Some questions :

        • What happens if we swap the North and South magnets ?
        • What happens if we use the AC motor connection ?
        • Can you think of a way to reduce contact bounce on the motor contacts ?

        Contact bounce happens when we open or close a switch. This causes false counting of pulses.

        Here’s the setup :


        Motor counter




      • #8562

          Hi Frank,

          Once again, great idea, demonstration and learning opportunity!  Thank you very much.  Best, M.

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