56. Solenoid Valve Relay Selection
1. Component Purpose
A solenoid valve is an electrically controlled mechanical valve used in fluid/gas systems. The controller energizes the relay to open or close the valve. The relay isolates the controller from the 24V valve circuit.
Since the valve draws only 1.2A, a ≥3A contact rating gives adequate margin. The valve is a 24VDC inductive load, so a flyback diode across the valve is also recommended.
Required: General Purpose · 12VDC coil · SPST-NO or SPDT · ≥3A contacts · 24VDC rated · Non Latching · Through Hole
2. How to Find It on DigiKey
Go to DigiKey.com → Relays → Power Relays
Apply these filters:
- Coil Voltage → 12VDC
- Contact Form → SPST-NO (1 Form A) or SPDT (1 Form C)
- Contact Rating (Current) → 3A or higher
- Coil Type → Non Latching
- Mounting Type → Through Hole
- Part Status → Active
Tip: Solenoid valves are inductive loads. Always add a flyback diode across the valve terminals to protect the relay contacts from voltage spikes when the valve de-energizes.
3. Key Specifications & What They Mean
| Specification | Required | Why |
|---|---|---|
| Coil Voltage | 12VDC | Matches controller driver supply. |
| Contact Form | SPST-NO or SPDT | Only NO switching needed. |
| Contact Current | ≥3A | Valve draws 1.2A; margin for DC arcing. |
| Switching Voltage | 24VDC rated | Must handle 24V DC load voltage. |
| Coil Type | Non Latching | Standard energize/de-energize control. |
| Mounting | Through Hole, PC Pin | Standard PCB mount. |
| Temp Range | −40°C to +85°C | Industrial conditions. |
| Safety Approval | cURus or equiv. | Product certification. |
4. Selecting a Safe, Production-Ready Part
The filtered list will show matching parts. Before you pick one, check: Is it Active? Is stock available? Is the manufacturer reputable? Is a datasheet available?
Full checklist: How to Select a Safe, Production-Ready Component — EWskills Guide