Hi All,

I need to power up 10 watts solenoid Valve using Arduino signal(5V) and also using EL817 & IRF5305S mosfet(pls refer my diagram). Based on the attached diagram , i am getting 12v .640ma current but need approx 840 ma current to execute my solenoid valve. Expert pls review my schematic and help me to increase the current.

Thanks
Rajesh

 

Added correct schematic.

 

Eliminate that unmarked resistor from the gate. Connect pin4 of the 817 directly to the gate
Check that the voltage on pin4 is low when activated.

 

Eliminate that unmarked resistor from the gate. Connect pin4 of the 817 directly to the gate
Check that the voltage on pin4 is low when activated.

Thank you for your instant reply. I have modified(removed resister) as suggested but the current dropped from 640ma to 600ma.

 

See

 

See
View attachment 339110

Thank you so much for detail diagram . Note that , I don't want to use any relay for this project and the mosfet(D) need re return the required volt (12V 840ma). Pls advise.


Thanks

 

hi nueon,
That MOS FET should be able to supply well in excess of 840mA.
What is the voltage across pins 3 and 4 of the EL817 in the On and Off States.
Also, what is that series resistor in the FET Gate?
E

 

See

 

If you're still getting insufficient drain current, try reducing the value (presently 1k) of the resistor in series with the LED.

 

hi nueon,
That MOS FET should be able to supply well in excess of 840mA.
What is the voltage across pins 3 and 4 of the EL817 in the On and Off States.
Also, what is that series resistor in the FET Gate?
E
View attachment 339116

Thank you so much.

#The on state the voltage across 4 & 3 - 0.13v
#off state -12.08v
#The Series resister in the FET gate is 1K, now its removed.
for your reference added the schematic again

 

If you're still getting insufficient drain current, try reducing the value (presently 1k) of the resistor in series with the LED.

Thank you for your response . I have reduced from 1k to 330 ohm. No luck .

 

hi n,
You should have ~840mA through the solenoid, IF the solenoid resistance is approx 14 Ohms.
Have you checked the solenoid resistance?
E

Also is the 12V PSU capable of supplying 840mA???

 

hi n,
You should have ~840mA through the solenoid, IF the solenoid resistance is approx 14 Ohms.
Have you checked the solenoid resistance?
E

Also is the 12V PSU capable of supplying 840mA???

I have connected the Solenoid valve directed to the 12V 1AMP PSU and its working and it took 820ma.

 

See

 

I have reduced from 1k to 330 ohm. No luck

Try removing/bypassing the green LED (you could drive it via a resistor from the solenoid connection instead).

 

Why not put the solenoid valve between the positive supply and the drain. That way you are not subtracting the source to gate voltage from the supply voltage. (Or use a P channel mosfet as suggested in post #14)
Edit. Ignore this post. I was thinking that you were using an N channel mosfet.
Les.

 

I don't see any voltage measurements. Activate the switch with the solenoid connected and measure the voltages:

1. between the source of the MOS FET and ground
2. between the drain of the MOS FET and ground
3. the voltage across the solenoid.

If the voltage between source and ground is correct and the voltage between the drain and ground is low, you have a faulty FET.
If the voltage between source and ground is low and the voltage between the drain and ground is low, you have faulty wiring between the supply and the FET.
If the voltage between drain and ground is correct and the voltage across the solenoid is low, you have faulty wiring between the switch and the solenoid.

 

I don't see any voltage measurements. Activate the switch with the solenoid connected and measure the voltages:

1. between the source of the MOS FET and ground
2. between the drain of the MOS FET and ground
3. the voltage across the solenoid.

If the voltage between source and ground is correct and the voltage between the drain and ground is low, you have a faulty FET.
If the voltage between source and ground is low and the voltage between the drain and ground is low, you have faulty wiring between the supply and the FET.
If the voltage between drain and ground is correct and the voltage across the solenoid is low, you have faulty wiring between the switch and the solenoid.

Thank you so much.
Now its working as expected.

Actually this is just a POC and using Breadboard to experiment this. The issue is breadboard and lost 200ma in the wiring current due to which Solenoid is not switching on.

Thank you so much to all the members contributed to this conversation.!!!!!