# Regarding solenoid valve

Can I only use one 12V DC power supply for two solenoid valves? I got connect the solenoid valves with a 5V 4 channel relay module with arduino as my microcontroller. Each of the solenoid valve is 12V, 2A. The power supply i using is 12V 2A, and i also got connect each valve with 1N4001 Rectifier Diode.

• yes you can, if the power supply is able to source the required current Apr 21, 2021 at 16:58
• The power supply i using is 12V 2A, and i also got connect each valve with 1N4001 Rectifier Diode, is it enough to support the two solenoid valves? Apr 21, 2021 at 17:55
• "Both the solenoid valve is 12V, 2A." Does that mean each valve is rated at 2A or both of them together? Apr 21, 2021 at 18:02
• Each of them are rated as 12V, 2A. Not add together. Apr 21, 2021 at 18:25

• Each solenoid requires 2 A.
• Your power supply is rated for 2 A.
• You can power one solenoid valve at a time.
• You would need a 4 A supply to power both of your solenoids.
• The diodes won't make an extra 2 A appear out of nowhere.

simulate this circuit – Schematic created using CircuitLab

Figure 1. Snubber diodes. You can still only power one 2 A solenoid from a 2 A supply.

The diodes should be connected as shown. Normally they don't conduct but when the relay contacts open they provide a decay path for the current and protect the relay contacts from arcing damage.

simulate this circuit

Figure 2. As suggested by @SpehroPefhany, this arrangement ensures that only one solenoid can be energised at a time with SV1 getting precedence.

• +1 OP could interlock one channel through the N.C. contact to prevent both being powered at once. Apr 21, 2021 at 18:38
• Good idea. Done. Apr 21, 2021 at 18:50
• Do you mean power supply should be 12V 4A? Apr 22, 2021 at 7:10
• @Anohana, what part of my answer did you not understand? Apr 22, 2021 at 8:33
• @Transistor, i understand that based on your answer, only one solenoid valve can be powered on at a time. Since i need both the solenoid valves to be powered at the same time, is it the power supply that i used should be 12V and 4A? Based on these two sentences: You can power one solenoid valve at a time. You would need a 4 A supply to power both of your solenoids. Apr 22, 2021 at 11:09