Questions about my first circuit

ian field

Joined Oct 27, 2012
6,536
Hello,

To start with, the fan is made for 5 Volts.
According to the datasheet it will work from 3 to 6 Volts.

Bertus
On one occasion I run a fan from a PC PSU at 17V - I had an ultra-slim PSU zip-tied to the light pendant flex, running a fan to chop up moths, wasps etc as they flew round the light bulb.

At 5V wasps just bounced off the fan blades - and got pretty pissed!!! The 12V rails wouldn't power the fan unless the 5V rail was loaded, so I hung the fan from +5V to -12V.

At 17V the wasps still bounced off - but the concussion made them stupid enough to keep trying till they disintegrated.
 

Thread Starter

John Fraskos

Joined Mar 3, 2015
19
The problem with using a resistor to limit current is that the fan is not drawing a constant current. It is energizing different coils at different times. The current draw that you calculate from the voltage and power is an average. In reality, it might be drawing twice as much current when a coil is activated and almost no current when no coil is activated. This means that if you calculate a resistor to drop the extra voltage, the voltage seed by the fan at different times will range from less than 5V to nearly the full 9V. And 9V could damage the electronics.
Got it, thanks!

Building yourself a 5V regulated power supply is a very good noob project and will come in very handy down the road. I highly suggest you go for it.
I will definitely do this. Thanks guys!
 
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