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How to connect thermistor without a PIC

  1. Dec 4, 2012 #1
    Hey hello,
    I am new in electrical system design. I almost know nothing. I need your help. And I have to control a DC motor's speed. My DC motor is 6V and I am not going to use a PIC. Is it possible or not I thought it was possible but as I said I know nothing.
    I thought of buying a NTC thermistor and connecting it into the system so if tempreture is high, resistance is going to be lower than it was. And my DC motor will gain more speed.
    But I searched almost all the internet I couldnt find a proper answer about connecting it into the ststem. I tryed to connect it serially with my DC motor but it doesnt really work. I saw some parallel connected system designs they got a resistor and a thermistor parallel connected.

    If you can help me I would be soo happy :) Thanks.
  2. jcsd
  3. Dec 4, 2012 #2


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    Staff: Mentor

    Welcome to the PF.

    I'm not following what you want to do with the thermistor. But to control DC motor speed, it is usually done with a pulse width modulation (PWM) circuit. If the DC is 6V all the time, the motor is at maximum speed. If you feed it a 50% duty cycle square wave 6V on, 0V off, at some reasonable frequency, the motor will run at less than full speed.

    If you do a Google search on PWM speed control circuits for DC motors, you should get some good ideas...
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