They look OK.
Although in the diag they show the load in the -ve output side. and the power fed to +ve.
Max.

 

@MaxHeadRoom so I am trying to make this circuit on the breadboard

I have following connection I have not connected SMPS yet because I do not want to damage any part's

I made a prototype circuit if do you see any wrong connection please let me know

IRLN540 MOSFET IC



Below is a more clear image

 

You should have a resistor from gate to ground, something like 10k will do. This ensures no stray triggering of the MOSFET until the micro outputs 5V to the pin (else gate is held at zero), especially at power up....
Back EMF diode should be as close to the coil as possible.

 

You should have a resistor from gate to ground, something like 10k will do. This ensures no stray triggering of the MOSFET until the micro outputs 5V to the pin (else gate is held at zero), especially at power up....
Back EMF diode should be as close to the coil as possible.

Does circuit looks okay ?

 

That looks good. Here http://www.redrok.com/MOSFET_IRL540N_100V_36A_44mO_Vth2.0_TO-220.pdf is the datasheet for the FET.

Note a few parameters. Vgs threshold. That's a good indication that it can be driven by a logic signal. Usually somewhere in the datasheet LOGIC level is used as well.

Max gate voltage is another concern.

When you do look at Vgs, you have to look at the graph (your load) of Vgs and current and how much Vgs you have available.

Igss is the reason for the 10K. You have to have a place for 100 nA to go in this case. The lower the value (the 10K), the faster the turn off.

 

That looks good.

I made a circuit connection for two loads. I just want to make sure that there is nothing wrong in the connection
Hope it would also okay ?

 

Looks OK. The diodes should be as close to the load as possible and power wiring should be as close to a home run as possible, These are guidelines.

 

Looks OK. The diodes should be as close to the load as possible and power wiring should be as close to a home run as possible, These are guidelines.

Is it necessary to do this? because I have load with 1-meter long power wiring I can't place diode close to load

 

They are guidelines. if you activate the solenoids every 10s, it might be a problem. If every fer hours then maybe not.

The primary reason for the diode is to protect the driver which the diode will do if it's close or far away.
The secondary reason is that the spike will radiate EMI/RFI if you use unshielded cables. Shielding reduces RFI and twisting reduces EMI,hence the use of twisted pair shielded cables. Running the valve cable close to other instrumentation is another problem.

So, like I said, sometimes it matters.

I used shielded power cords to heaters when they were operated in an RF plasma chamber at 13.56 MHz.

 

They are guidelines. if you activate the solenoids every 10s, it might be a problem. If every fer hours then maybe not..

@KeepItSimpleStupid It might be a problem I have to activate solenoids on every 0.18

 

The thing is, it CAN affect other stuff. I'm not saying it will. You either have to be aware or plan for it.
Occasionally you missjudge.

I had to select a UPS that can run on generator power. Some won't. You have to know to ask. An always online UPS will generally have no issues.

Once I thought I made a homemade manual Mass Flow Controller readout computer compatible. Well almost.
Missed the 6 ground loops.

In the Macintosh II ERA, I was TOLD to use NuBus Cards. I wanted some other solution. management lost that battle.

I wanted a particular Instrument for semiconductor characterization. I was told no, it uses feedback. 17 years later, that kind of instrument was used in an upgrade.

Most of my decisions were good. One wasn't. I was dealing with a lot of money in a snapshot of time, but I could nt deliver by myself in a reasonable time frame. I didn;t ask for help. The technology didn;t exist when I started the project. That was a computer controlled monochometer with shutters and filters. One did later, but it was slightly inferior in performance.

Anyway, my selection of a computer/software/programming survived for 17 years with no changes in the software.

I wanted a server. I was told no. Many years later, we got a server for data. It was basically a SAMBA share set up by our computing center. We had no admin access and didn't have to worry about backups.

 

Hello, new member here, joined just 2 days ago. I have been looking for pretty-much this exact same setup. I needed to clean the Fuel Injectors on my Wife's car. I put together a BASIC Stamp microcontroller, small 5 and 12 volt power supply, an 8 channel relay board and an ultrasonic cleaner tank. This worked, but....... later decided that I had watched too many videos about Injector Testers. I was cycling this setup WAY TOO QUICKLY for cleaning. It worked well enough that the cleaning fluid was coming out the top of the injectors. What I NEEDED was something less mechanical than using relays and run with a longer On-time and shorter Off-time. I had already decided upon a "logic-level" Mosfet due to the power levels that a Stamp's pins can handle. But this thread put all my concerns together in one place. Many discuss using an optocoupler, to protect my toys, a diode to suppress flyback/flywheel surges, resistor to protect the possibility of the signal producer coming unhooked and others. But this was all put together in one read here! Now I can go build something that I may never need again, but who cares, I'll still enjoy the experience. Thanks for the website, article and info.