Hello,
I need a help with making right circuit for controlling solenoid latching valve (6VDC) with Arduino Uno. I am not sure how to use transistors in this specific case.
This is a 3 wire valve: one common anode and two cathodes. 7 Watts Latching impulse and 5 Watts Unlatching impulse.
The system is powered with 6V battery.
Seems you need two transistors to switch the two "cathodes" to ground.
5-7watt (~1Amp) is too much for a common (2N2222) transistor, and a darlington (TIP120) has a high dropout voltage, so you need to use logic level mosfets.
Use the first circuit in this link.
Leo..
I think I understand. Thank you Leo!
If I were OP, I'd post a link to the datasheet....
Hydra7:
Hello,I need a help with making right circuit for controlling solenoid latching valve (6VDC) with Arduino Uno. I am not sure how to use transistors in this specific case.
This is a 3 wire valve: one common anode and two cathodes. 7 Watts Latching impulse and 5 Watts Unlatching impulse.
The system is powered with 6V battery.
You have provided no link to the datasheet or product page for the valve. That's all you need to provide, and by far the best way to explain what it is, without risk of confusion or the need for further discussion.
I am sorry. This is the valve:
https://www.gemssensors.com/~/media/files/resources/na_english/catalogpages/catalog-j_bl-series.pdf
That datasheet covers multiple valves. Which ONE do you have?
It is BL3113-S44.
I have already said that it is 6VDC, common anode, 7 Watts Latching impulse and 5 Watts Unlatching impulse. I thought that it was enough information for making circuit.
Which one is "common anode":
NW
Are you sure about that mosfet? I need 1 amp impulse and the one you suggest is 30 amp?
A common NPN transistor used as a switch needs a base current of 10-20% of it's collector current.
That would mean about 150mA from an Arduino output pin (rated at ~20mA).
So not possible.
A darlington transistor only needs 1/250 in the base (4mA).
Not a problem for the Arduino pin, but a darlington has a dropout voltage of ~1volt at that current.
The supply should be 1volt higher to compensate.
It could get 50C hotter at that current if used continuously (not relevant here).
A mosfet switches almost without losses. Not relevant if it's a 3Amp or 30Amp or 300Amp mosfet.
Leo..
There ARE logic level MOSFETs in the 4, 5, 6 amp range but I couldn't recall a part #, anyway, because they're less frequently used, they probably cost a lot more than a 30 A. 
Parts in the AOD5xx family are N-channel MOSFETs, with the 508, 510, 514 all capable of gate drive from Arduino and very high currents.
https://www.digikey.com/products/en/discrete-semiconductor-products/transistors-fets-mosfets-single/278?k=aod5
I use them on this board, with the gates driven by 74HC595s.
