# Several 12v Logic Level Mosfets with Source to common Ground?

**URL:** <https://forum.arduino.cc/t/several-12v-logic-level-mosfets-with-source-to-common-ground/1068829>\
**Category:** General Electronics\
**Created:** [December 23, 2022, 4:40pm UTC](https://forum.arduino.cc/t/several-12v-logic-level-mosfets-with-source-to-common-ground/1068829 "2022-12-23T16:40:15Z")\
**Posts on this page:** 8\
**Page:** 1

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**Author:** ![freysbrewing](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/freysbrewing/32/246575_2.png) [@freysbrewing](https://forum.arduino.cc/u/freysbrewing)\
**Post date:** [December 23, 2022, 4:40pm UTC](https://forum.arduino.cc/t/several-12v-logic-level-mosfets-with-source-to-common-ground/1068829/1 "2022-12-23T16:40:15Z")

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Am I going in the wrong direction, or can two or more mosfets run their Source pins to a common ground and not interfere with each other?

Source --\> GND \<-- Source

And if that is allowed, will

Gate --\> 10kΩ resistor --\> Ground \<-- Source

also work in this setup? Or will the closest resistors to the power source drain energy from the mosfets farther away?

Breadboard layout designed with minimal use of jumpers & minimal footprint, so everything can be easily moved over to a circuit board & soldered. Mosfets are IRLZ44N. Solenoids are 12v. Pins 3&4 go to Arduino.

 ![Logic Level Mosfets with grounded common Source](https://europe1.discourse-cdn.com/arduino/original/4X/6/a/4/6a401e48c1b6fb18d976260425dc9ad1d240e412.jpeg)

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**Author:** ![LarryD](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/larryd/32/215550_2.png) [@LarryD](https://forum.arduino.cc/u/LarryD)\
**Post date:** [December 23, 2022, 5:07pm UTC](https://forum.arduino.cc/t/several-12v-logic-level-mosfets-with-source-to-common-ground/1068829/2 "2022-12-23T17:07:50Z")

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Your diagram looks okay.

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<div class="post-metadata">

**Author:** ![freysbrewing](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/freysbrewing/32/246575_2.png) [@freysbrewing](https://forum.arduino.cc/u/freysbrewing)\
**Post date:** [December 23, 2022, 5:10pm UTC](https://forum.arduino.cc/t/several-12v-logic-level-mosfets-with-source-to-common-ground/1068829/3 "2022-12-23T17:10:35Z")

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Thanks!

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**Author:** ![LarryD](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/larryd/32/215550_2.png) [@LarryD](https://forum.arduino.cc/u/LarryD)\
**Post date:** [December 23, 2022, 5:13pm UTC](https://forum.arduino.cc/t/several-12v-logic-level-mosfets-with-source-to-common-ground/1068829/4 "2022-12-23T17:13:11Z")

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If you want to generate a nice tight circuit consider this idea.

> [@Share tips you have come across](https://forum.arduino.cc/t/share-tips-you-have-come-across/428745/969):
>
> Further to post # 504 [https://forum.arduino.cc/t/share-tips-you-have-come-across/428745/504?u=larryd](https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fforum.arduino.cc%2Ft%2Fshare-tips-you-have-come-across%2F428745%2F504%3Fu%3Dlarryd&data=04%7C01%7C%7C9a790dde38ae41488fc708d9b12a87cf%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637735618494524175%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=UvnoAyqgbi6KGj7mJ%2Fvn2uQoxH4B3cUark3ALa5rNYo%3D&reserved=0) These Solderless Breadboard helpers are great for speeding up wiring.\*\* Other SMDs can be mounted on Machine Pin Headers as well. Below are a few more ways that you can take advantage of the footprints of SMDs. Some suggestions of use: \*\*pull-ups/pulldowns, switches, capacitors, ferrite beads, jumpers, current limiting for LEDs, test points. These helpers are: low profile, less likely to sh…

 ![B](https://europe1.discourse-cdn.com/arduino/original/4X/8/1/b/81b14c12a06f8b2fcb1854a88cdbd5afaaccb582.jpeg)

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<div class="post-metadata">

**Author:** ![freysbrewing](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/freysbrewing/32/246575_2.png) [@freysbrewing](https://forum.arduino.cc/u/freysbrewing)\
**Post date:** [December 23, 2022, 8:03pm UTC](https://forum.arduino.cc/t/several-12v-logic-level-mosfets-with-source-to-common-ground/1068829/5 "2022-12-23T20:03:05Z")

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Nice! Once my header's get in, I'll give that a try.

One more mosfet question - if the backside of the drain (where the screw goes) is too close to (or even touching) the other mosfet's backside drain, can that cause an arc or other issues?

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**Author:** ![gilshultz](https://avatars.discourse-cdn.com/v4/letter/g/67e7ee/32.png) [@gilshultz](https://forum.arduino.cc/u/gilshultz)\
**Post date:** [December 23, 2022, 8:05pm UTC](https://forum.arduino.cc/t/several-12v-logic-level-mosfets-with-source-to-common-ground/1068829/6 "2022-12-23T20:05:57Z")

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You did good. However you have no choice, the source of the each of the MOSFETs must go to ground; This is the best way to drive your load. Just be sure you use a solid ground and it is also connected to the ground of the Arduino. Connect the 12V power supply ground to the source then to the arduino. You probably do not need the FB diodes as the MOSFET you chose is avalanche rated. This rating allows you to eliminate the flyback diodes. They even tell you how much energy they will adsorb. You can check that rating against your solenoid current. You will need to capture this in a CAD program to make your PCBs. I use KiCad as it takes me from schematic capture to the Gerber files needed to make the PCB.

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<div class="post-metadata">

**Author:** ![LarryD](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/larryd/32/215550_2.png) [@LarryD](https://forum.arduino.cc/u/LarryD)\
**Post date:** [December 23, 2022, 8:38pm UTC](https://forum.arduino.cc/t/several-12v-logic-level-mosfets-with-source-to-common-ground/1068829/7 "2022-12-23T20:38:10Z")

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> [@freysbrewing](#):
>
> can that cause an arc or other issues

**Never** a good idea to let electronic components ever touch.

The tabs on the MOSFETs are connected to the Drain, **look at the data sheet.**

* * *

Inductive loads should almost always have a snubbing/kickback diode across their terminals.

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**Author:** ![system](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/system/32/1140315_2.png) [@system](https://forum.arduino.cc/u/system)\
**Post date:** [June 21, 2023, 8:38pm UTC](https://forum.arduino.cc/t/several-12v-logic-level-mosfets-with-source-to-common-ground/1068829/8 "2023-06-21T20:38:17Z")

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