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