AC 220V 1-Channel Optocoupler Isolation Voltage Detection Module

The AC 220V 1-Channel Optocoupler Isolation Module is designed to detect the presence of 220V AC mains voltage and provide an electrically isolated low-voltage output signal for a microcontroller, PLC, or control system.

The optocoupler provides isolation between the high-voltage AC detection side and the low-voltage logic side, making the module useful for monitoring whether an AC-powered circuit or device is energized.

It is suitable for Arduino projects, PLC systems, industrial automation, power-status monitoring, alarm systems, and AC voltage presence detection.

Technical Specifications

• Module Type: AC Voltage Detection / Optocoupler Isolation Module
• Number of Channels: 1
• AC Detection Input: 220V AC
• Logic-Side Supply: 3–5V DC
• Output: Digital Logic / TTL-Level Signal
• Isolation Method: Optocoupler / Photoelectric Isolation
• Microcontroller Compatibility: 3–5V Logic Systems
• PLC Compatibility: Can Be Used with 24V PLC Input Applications
• AC Input Connection: 2-Pin Screw Terminal
• Logic Connection: 3-Pin Interface
• Board Dimensions: Approx. 73 × 15mm

How It Works

The high-voltage input terminals are connected across the AC circuit that needs to be monitored.

When 220V AC is present, the input circuit activates the optocoupler, causing the low-voltage output to change logic state. A connected microcontroller or PLC can monitor this output to determine whether AC voltage is present.

Because the detection signal passes through an optocoupler, the low-voltage control circuitry is electrically separated from the AC detection circuit.

Microcontroller Interface

The low-voltage side can be interfaced with compatible microcontrollers and digital control systems.

Typical connections include:

VCC – Logic-Side Power Supply
GND – Logic Ground
OUT – Detection Signal Output

The logic-side supply is typically 3–5V DC.

The exact active HIGH/LOW behavior should be confirmed on the supplied board before programming the final control logic.

Applications

Ideal for AC mains presence detection, Arduino projects, PLC monitoring, industrial automation, equipment status monitoring, AC power failure detection, alarm systems, relay and contactor monitoring, smart-home projects, control panels, and embedded monitoring systems.

For example, a microcontroller can use the module to determine whether a 220V appliance, machine, lighting circuit, or other AC line is energized without directly connecting the microcontroller to mains voltage.

Important Safety Note

This module is designed to work with 220V AC mains voltage. Potentially lethal voltage is present on the high-voltage section of the PCB whenever the AC input is connected.

Do not touch the module, terminals, solder joints, or components on the high-voltage side while powered.

The module should be installed inside a suitable insulated enclosure with adequate electrical clearances and protection against accidental contact.

Always disconnect mains power before installing, adjusting, or servicing the module. Mains-voltage installation should be performed by a suitably qualified person.

Optocoupler isolation provides signal isolation but does not make exposed high-voltage parts safe to touch.

Package Includes

1 × AC 220V 1-Channel Optocoupler Isolation Voltage Detection Module