57. DPDT Relay for Motor Direction Control
1. Component Purpose
To reverse a DC motor’s direction, you need to reverse the polarity of the voltage applied to it. A DPDT (Double Pole, Double Throw) relay has two sets of changeover contacts that can swap the motor’s connections simultaneously.
When the relay is de-energized, the motor runs in one direction. When energized, both poles switch together, reversing the motor’s polarity and spinning it the opposite way.
Required: General Purpose · 12VDC coil · DPDT (2 Form C) · ≥5A contacts · 12VDC rated · Non Latching · Through Hole
2. How to Find It on DigiKey
Go to DigiKey.com → Relays → General Purpose Relays
Apply these filters:
- Coil Voltage → 12VDC
- Contact Form → DPDT (2 Form C)
- Contact Rating (Current) → 5A or higher
- Coil Type → Non Latching
- Mounting Type → Through Hole
- Part Status → Active
Important: DPDT is not the same as 2x SPDT. A DPDT relay switches both poles simultaneously with a single coil — critical for safe motor polarity reversal. Using two separate SPDT relays risks a brief short if they don’t switch at exactly the same time.
3. Key Specifications & What They Mean
| Specification | Required | Why |
|---|---|---|
| Coil Voltage | 12VDC | Matches driver supply. |
| Contact Form | DPDT (2 Form C) | Two poles needed for polarity reversal. |
| Contact Current | ≥5A | Motor draws 2A; margin for DC arc + inrush. |
| Switching Voltage | 12VDC rated | Must be rated for DC switching. |
| Coil Type | Non Latching | Direction set by control signal state. |
| 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