16A Bistable Self-Locking Relay Board | Power-Off Memory

16A Bistable Self-Locking Relay Board — Power-Off Memory & Reverse Polarity Protection

This compact yet powerful bistable relay module is designed for engineers, hobbyists, and automation enthusiasts who need a reliable, self-holding switching solution. Operating across a wide DC voltage range (10V–28V), this board retains its last output state even when power is removed — no continuous power draw required to hold the relay position. Each power-on pulse toggles the output state, making it ideal for latching control circuits, smart home automation, industrial switching, and DIY electronics projects.

Key Features

• Bistable / Self-Locking Operation: The relay holds its last switched state (open or closed) when power is disconnected — true power-off memory with zero standby holding current needed.
• Wide Input Voltage Range: DC 10V to 28V — compatible with 12V and 24V systems. Higher input voltage enables faster switching speeds.
• 16A Output Capacity: Rated for 16A at 250VAC, suitable for controlling lights, motors, appliances, and other high-load devices.
• Reverse Polarity Protection: Built-in protection prevents module damage or unintended operation if the power supply connections are accidentally reversed.
• Passive Output (Isolated Contacts): The relay contacts are fully isolated from the module's power supply, ensuring safer and cleaner circuit integration.
• Fast Switching: Switching action completes in approximately 0.1 seconds, allowing up to 5 toggles per second.
• Normally Open + Normally Closed Outputs: One set of NO/NC relay contacts provided for flexible wiring options.
• Wide Operating Temperature: -30°C to +75°C, suitable for demanding environments.

Specifications

How It Works

Each time the module receives a power-on pulse, it toggles the relay output to the opposite state. For example: first pulse → relay connects (NO contact closes); second pulse → relay disconnects (NO contact opens). When power is removed entirely, the relay mechanically holds its current state indefinitely — no power is required to maintain position. This makes it perfect for battery-conscious designs and circuits that must preserve state across power cycles.

Package Contents

• 1× Bistable Self-Locking Relay Module

Note: Slight color variation may occur due to monitor/screen differences. Please allow ±1–10mm measurement tolerance due to manual measurement processes.

For general guidance on safe electrical wiring and component handling, visit the OSHA Electrical Safety Resource.

Frequently Asked Questions

Q: What does "bistable" or "self-locking" mean on this relay board?

A: A bistable relay has two stable mechanical positions — it stays in whichever state it was last switched to, even with no power applied. This relay board uses a magnetic bistable mechanism, so once toggled, it holds its position (open or closed) without drawing any continuous coil current. This is ideal for energy-efficient designs where the load state must be preserved during power-off conditions.

Q: What input voltage does this relay module require?

A: This relay board supports a wide DC input voltage range of 10V to 28V, making it compatible with common 12V and 24V systems. Higher input voltages generally result in faster switching speeds and higher switching frequencies (up to 2 switches per second at 24V).

Q: Can this module handle AC loads, and what is the maximum current rating?

A: Yes — the output relay contacts are rated for 16A at 250VAC. The contacts are passively isolated from the module's own power supply, so they can safely switch AC or DC loads independently of the control voltage.

Q: What happens if I accidentally connect the power supply in reverse polarity?

A: This module includes built-in reverse polarity (reverse power connection) protection. If the positive and negative leads are connected incorrectly, the module will simply not operate — it will not be damaged and will not produce unintended output, keeping your circuit and connected devices safe.