4-Channel Relay Boards for Sale: Price, Selection & Local Stock at Communica

Quality 4-Channel Relay Boards in Stock

Whether you're automating a school STEM project, prototyping a smart home solution, or building robust industrial controls, 4-channel relay boards are a cost-effective way to switch multiple loads. At Communica, you'll find an extensive lineup of relay modules-5V or 12V coils, screw terminal outputs, and compatibility with microcontrollers (Arduino, Raspberry Pi, ESP32) and logic PLCs.

Why Use a 4-Channel Relay?

• Switch up to four circuits independently with one compact module
• Control AC loads (appliances, lights, pumps) or higher-voltage DC loads safely
• Isolated trigger circuits-ideal for microcontroller, PLC, or sensor-based control
• Expandable in banks for scalable automation or IoT systems

Relay Module Options & Features

How to Choose the Right 4-Channel Relay

• Check coil voltage matches your control circuit (5V for Arduino/Raspberry Pi, 12V for industrial PLC).
• Confirm maximum switching current/voltage is above your load's demands. For mains AC, verify 220-240VAC relay rating.
• Opt for optoisolated inputs if mixing high/low voltage environments or noisy loads.
• Consider form factor-PCB mount vs. DIN rail adapters for panel installs.

Popular brands and module families found at Communica include Keyestudio, Songle, and DFRobot, all widely supported in maker, student, and light industrial settings in South Africa.

Pricing & Stock: What to Expect at Communica

4-channel relay boards at Communica are typically available in the ZAR80-ZAR250 range, depending on the brand, coil voltage, and input/output features. Pricing is updated seasonally, reflecting local availability and exchange rates. You can easily check live stock and price status for immediate branch pickup or courier delivery across South Africa.

Wiring Example: Integrating with Arduino

+5V (Arduino VCC) ------+-----------------------+
                        |                       |
IN1 (D7) ---- resistor --+----[relay 1 input]    |
IN2 (D6) ---- resistor ------[relay 2 input]     |
IN3 (D5) ---- resistor ------[relay 3 input]     |
IN4 (D4) ---- resistor ------[relay 4 input]     |
GND (Arduino) ----------------[relay GND]--------+

Always use optoisolated modules when interfacing microcontrollers with high-voltage AC loads. For switching 220V mains in South Africa, ensure proper enclosure and follow safe wiring practices.

Typical Applications in South Africa

• Automated irrigation (farms or gardens)
• Remote appliance switching (via IoT platforms)
• Industrial panel builds (small automation jobs)
• Classroom STEM projects (logic control training)

Order & Support Notes

• Orders include a VAT invoice for education or business claims
• In-branch technical staff can assist with module selection and troubleshooting
• Bulk quantities are available for schools and industry-please check lead times for large projects
• Accessory bundles: pick up jumper cables, terminal blocks, and enclosures in the same cart

Troubleshooting Your Relay Board

• If relays don't click: check supply voltage/polarity, and verify trigger logic (active low or high)
• Rapid relay chattering: investigate floating control pins, debounce logic, or excessive coil current draw
• AC load not switching: ensure relay rating matches your load and connections are secure

Sources

• Relay Boards at Communica
• Arduino Relay Integration Guide
• DFRobot Official
• Keyestudio Relay How-To
• Communica Branch Hours & Pickup