Transistor Controlled Fan

**Start Date:**Aug 5, 2023

Transistor Controlled Fan

After controlling a variable output voltage, this project controls a variable output current.

For now, the current is either high or low. Following on will be an attempt to set current to a range of values.

There are two main parts to this circuit - the microchip and the transistor section. The microchip controls the output voltage, and works the same as the case for turning an LED on and off ( see the LED post for details on how this works ).

The transistor section turns this voltage into a current, and is slightly more cumbersome. Once the mathematical relationships are figured out, it all works fairly easily though. The math involved is needed to figure out what resistors need to be connected at the three pins of the transistor, to create the desired current output. The most complex math here is an exponential function.

With the technical details out of the way, see the results below...

To download the file, click here:

For now, the current is either high or low. Following on will be an attempt to set current to a range of values.

There are two main parts to this circuit - the microchip and the transistor section. The microchip controls the output voltage, and works the same as the case for turning an LED on and off ( see the LED post for details on how this works ).

The transistor section turns this voltage into a current, and is slightly more cumbersome. Once the mathematical relationships are figured out, it all works fairly easily though. The math involved is needed to figure out what resistors need to be connected at the three pins of the transistor, to create the desired current output. The most complex math here is an exponential function.

With the technical details out of the way, see the results below...

To download the file, click here: