on video how to make a simple dc motor speed control circuit

 

how to make a simple dc motor speed control circuit, As can be seen the mosfet is rigged as a source follower or a common drain mode, to learn more about this configuration you may refer to this post, which discusses a BJT version, however the working principle remains the same.

In the above DC motor controller design, the pot adjustment creates a varying potential difference across the gate of the mosfet, and the source pin of the mosfet simply follows the value of this potential difference and adjusts the voltage across the motor accordingly.

It implies that the source will be always 4 or 5V lagging behind the gate voltage and vary up/down with this difference, presenting a varying voltage between 2V and 7V across the motor.

When the gate voltage is around 7V, the source pin will supply the minimum 2V to the motor causing a very slow spin on the motor, and 7V will be available across the source pin when the pot adjustment generates the full 12V across the gate of the mofet.

This happens because the difference between the gate and the source pin of the mosfet must be always around 5V, in order to enable the mosfet to conduct optimally.

Anyway, the above configuration helps to enforce a smooth speed control on the motor, and the design could be built quite cheaply.

A BJT could be also used in place of the mosfet, and in fact a BJT would produce a higher control range of about 1V to 12V across the motor.

 

how to make a simple dc motor speed control circuit, As can be seen the mosfet is rigged as a source follower or a common drain mode, to learn more about this configuration you may refer to this post, which discusses a BJT version, however the working principle remains the same.

In the above DC motor controller design, the pot adjustment creates a varying potential difference across the gate of the mosfet, and the source pin of the mosfet simply follows the value of this potential difference and adjusts the voltage across the motor accordingly.

It implies that the source will be always 4 or 5V lagging behind the gate voltage and vary up/down with this difference, presenting a varying voltage between 2V and 7V across the motor.

When the gate voltage is around 7V, the source pin will supply the minimum 2V to the motor causing a very slow spin on the motor, and 7V will be available across the source pin when the pot adjustment generates the full 12V across the gate of the mofet.

This happens because the difference between the gate and the source pin of the mosfet must be always around 5V, in order to enable the mosfet to conduct optimally.

Anyway, the above configuration helps to enforce a smooth speed control on the motor, and the design could be built quite cheaply.

A BJT could be also used in place of the mosfet, and in fact a BJT would produce a higher control range of about 1V to 12V across the motor.

 

how to make a simple dc motor speed control circuit, As can be seen the mosfet is rigged as a source follower or a common drain mode, to learn more about this configuration you may refer to this post, which discusses a BJT version, however the working principle remains the same.

In the above DC motor controller design, the pot adjustment creates a varying potential difference across the gate of the mosfet, and the source pin of the mosfet simply follows the value of this potential difference and adjusts the voltage across the motor accordingly.

It implies that the source will be always 4 or 5V lagging behind the gate voltage and vary up/down with this difference, presenting a varying voltage between 2V and 7V across the motor.

When the gate voltage is around 7V, the source pin will supply the minimum 2V to the motor causing a very slow spin on the motor, and 7V will be available across the source pin when the pot adjustment generates the full 12V across the gate of the mofet.

This happens because the difference between the gate and the source pin of the mosfet must be always around 5V, in order to enable the mosfet to conduct optimally.

Anyway, the above configuration helps to enforce a smooth speed control on the motor, and the design could be built quite cheaply.

A BJT could be also used in place of the mosfet, and in fact a BJT would produce a higher control range of about 1V to 12V across the motor.

 

how to make a simple dc motor speed control circuit, As can be seen the mosfet is rigged as a source follower or a common drain mode, to learn more about this configuration you may refer to this post, which discusses a BJT version, however the working principle remains the same.

In the above DC motor controller design, the pot adjustment creates a varying potential difference across the gate of the mosfet, and the source pin of the mosfet simply follows the value of this potential difference and adjusts the voltage across the motor accordingly.

It implies that the source will be always 4 or 5V lagging behind the gate voltage and vary up/down with this difference, presenting a varying voltage between 2V and 7V across the motor.

When the gate voltage is around 7V, the source pin will supply the minimum 2V to the motor causing a very slow spin on the motor, and 7V will be available across the source pin when the pot adjustment generates the full 12V across the gate of the mofet.

This happens because the difference between the gate and the source pin of the mosfet must be always around 5V, in order to enable the mosfet to conduct optimally.

Anyway, the above configuration helps to enforce a smooth speed control on the motor, and the design could be built quite cheaply.

A BJT could be also used in place of the mosfet, and in fact a BJT would produce a higher control range of about 1V to 12V across the motor.