Fans slow down when extruder or hotbed activated

[_kaktus_]

[quote=JohnDeere630 post_id=83216 time=1521259098 user_id=52773]
... It seems that a 3-wire fan may solve your issue.
[/quote]

Gentlemen ATTENTION.

Fan with a three-pin connector has signals:

red -> Vcc
black -> GND
yellow -> tacho

Vcc -> supply voltage - the so-called +
GND -> power ground - in other words zero
tacho -> OUTPUT pulses for speed counting, by the monitoring system.
Usually, two impulses are sent for one rotation.

In order to control the rotational speed of such a fan, it is most often controlled by a suitable square-wave signal with variable fill (PWM).
.
_The_ _fan_ _should_ _not_ _be_ _connected_ _directly_ _to_ _the_ _μC_ _port_. You can destroy μC.

[JustinSB]

Thanks for the Pin number William.