on video How to build the simplest DC Motor Speed Controller

 Connect a heatsink to the MOSFET

POT can also be used to directly control a motor. But it needs to be a high power POT (unless the motor is really low power)

This circuit is very inefficient(but its really simple!) in controlling high power(torque) motors. To control such motor you're better off with PWM. PWM is much more efficient.

Refer the "Connections Diagram" frame in the video for connections.

This the simplest way to control the speed of a "normal" DC motor.

The MOSFET is configured as a source follower. The output voltage is gate voltage minus threshold voltage. The variable resistor(Potentiometer,"POT") controls the voltage at the gate. The voltage at gate with reference to source(Vgs) determines the current flow through the motor. When the Vgs reaches around 2v the channels starts to open, as we keep increasing Vgs ,the channel becomes wider allowing greater current to flow.

Here a circuit to control DC motor speed using MOSFET and Potentiometer is demonstrated. The MOSFET used is CEP7030L which is N-Channel Enhancement Mode Field Effect Transistor(MOSFET). This MOSFET transistor can be salvaged from old PC power supply units(PSU) as was done in this demonstration. Using such power MOSFET we can apply high voltage to the DC motor without heating the power MOSFET. Here the DC motor has voltage rating of 12V. The potentiometer is a 10KOhm potentiometer. An additional resistor of 1MOhm is also used. 

In the circuit schematic above, 12V positive terminal is connected directly to the drain of the CEP7030L power MOSFET. One terminal of the DC motor is connected to the source of the MOSFET while the other terminal of the motor is connected back to the negative terminal of the 12V battery. The 10kOhm potentiometer middle terminal is connected to the gate of the transistor. The other two sides are connected to the positive and negative wires. Thus the potentiometer is used as a voltage divider. The 1MOhm resistor is used to bias the transistor. This was explained in the tutorial

Here we have shown how to build a DC motor speed controller using Potentiometer and power MOSFET salvaged from PC power supply unit. One an also build simple DC motor at home and this controller can be applied also. For robotics more sophisticated motor controller such L298N IC as can be used as is demonstrated in the tutorial DC motor control using L293D Motor Shield and Arduino.

 Connect a heatsink to the MOSFET

POT can also be used to directly control a motor. But it needs to be a high power POT (unless the motor is really low power)

This circuit is very inefficient(but its really simple!) in controlling high power(torque) motors. To control such motor you're better off with PWM. PWM is much more efficient.

Refer the "Connections Diagram" frame in the video for connections.

This the simplest way to control the speed of a "normal" DC motor.

The MOSFET is configured as a source follower. The output voltage is gate voltage minus threshold voltage. The variable resistor(Potentiometer,"POT") controls the voltage at the gate. The voltage at gate with reference to source(Vgs) determines the current flow through the motor. When the Vgs reaches around 2v the channels starts to open, as we keep increasing Vgs ,the channel becomes wider allowing greater current to flow.

Here a circuit to control DC motor speed using MOSFET and Potentiometer is demonstrated. The MOSFET used is CEP7030L which is N-Channel Enhancement Mode Field Effect Transistor(MOSFET). This MOSFET transistor can be salvaged from old PC power supply units(PSU) as was done in this demonstration. Using such power MOSFET we can apply high voltage to the DC motor without heating the power MOSFET. Here the DC motor has voltage rating of 12V. The potentiometer is a 10KOhm potentiometer. An additional resistor of 1MOhm is also used. 

In the circuit schematic above, 12V positive terminal is connected directly to the drain of the CEP7030L power MOSFET. One terminal of the DC motor is connected to the source of the MOSFET while the other terminal of the motor is connected back to the negative terminal of the 12V battery. The 10kOhm potentiometer middle terminal is connected to the gate of the transistor. The other two sides are connected to the positive and negative wires. Thus the potentiometer is used as a voltage divider. The 1MOhm resistor is used to bias the transistor. This was explained in the tutorial

Here we have shown how to build a DC motor speed controller using Potentiometer and power MOSFET salvaged from PC power supply unit. One an also build simple DC motor at home and this controller can be applied also. For robotics more sophisticated motor controller such L298N IC as can be used as is demonstrated in the tutorial DC motor control using L293D Motor Shield and Arduino.