Voltage drop using IRFZ44 MOFSET as relay

Hi all,

I could really use some help. I am using a Wemos D1 Mini (ESP8266) to power a 3-5V 125mA DC motor. Ultimately it will run on a 3.7V 18650 battery.

I use D2 on the ESP to switch the IRFZ44 MOSFET and use a 1N4001 rectifier diode in the circuit as attached.

When I use the 3.3v from the ESP to power the motor directly, it runs perfectly. However, when I use the IRFZ44 as relay, the maximum voltage the motor gets is 1.85V from the 3.3V total supplied. If I run the system on the 3.7V battery (delivering 4V actually on load) the motor gets 2.5V. In both situations it looks like I lose 1.5V in the MOSFET that I shouldn't.

I am totally lost here. Any1 got a suggestion?

Arco

Special Member

The IRFZ44 is not a logic mosfet, you need the IRLZ44.
(you cannot drive the IRFZ44 from 3.3v, you need at least 4+ volts)

R1 should also be smaller (33...47Ω)

[Bericht gewijzigd door Arco op woensdag 15 december 2021 16:17:41 (16%)

Arco - "Simplicity is a prerequisite for reliability" - hard-, firm-, en software ontwikkeling: www.arcovox.com

Thank you Arco!

I did use the wrong MOSFET. Got myself a bunch of IRLZ44's and now it works like a charm _/-\o_

8)7 mistake

[Bericht gewijzigd door Auraxis op donderdag 16 december 2021 13:16:23 (98%)