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Learn about 2-channel relay boards for automation in South Africa. Find specs, wiring examples, common brands, and local availability at Communica.
Switch AC or DC loads for smart home, robotics, or lab projects.
Understand voltage, trigger logic, and how to connect relay modules.
Browse 2-channel relay boards in stock at Communica branch or online.
2-channel relay modules are compact boards that integrate two independent relay switches, allowing you to control high-power devices (like appliances, lighting circuits, pumps, or motors) from a low-voltage control system such as Arduino, PLCs, or Raspberry Pi. Common in South African home automation, security, robotics, and educational setups, these boards provide a safe, isolated way to interface digital logic to AC or DC loads up to several amps.
Ideal for hobby, tertiary, and industrial labs, relay boards typically feature opto-isolation, indicator LEDs, and screw terminal outputs-simplifying integration and troubleshooting. Popular use cases include automated gate control, smart irrigation, or switching mains sockets for test automation, with availability through distributors like Communica.
| Feature | Typical Value | What It Means |
|---|---|---|
| Relay Contact Rating | 10A @ 250VAC / 10A @ 30VDC | Maximum switched load per relay |
| Trigger Voltage | 3.3V / 5V (TTL logic) | Matches microcontroller/PLC output |
| Relay Type | SPDT (Single Pole Double Throw) | Each relay has NO/NC contacts |
| Isolation | Opto-isolated inputs (common) | Prevents back-feed & cross-talk |
| Indicator | Relay ON LED | Visual feedback for each channel |
Communica stocks a variety of brands and board layouts, including standard relay modules and compact PCB-mountable versions. Look for relay voltage (5V or 12V), required trigger logic (active-high or active-low), and whether both relays are fully independent.
Below is a simplified ASCII diagram for connecting a 2-channel relay board to an Arduino to control a 230V light and a 12V pump (both loads isolated for safety):
[GND]---+ +--[Relay1 NO]--[Light 230V L]--+
| +-----+ | |
[5V]----+----+---> | VCC |--------+ +--[Relay2 NO]--[Pump 12V +]--+
| +-----+ | |
[Arduino Pins] [Relay In1/In2]
Always follow best practices: ensure mains wiring is completed by a qualified electrician; use fuses and insulation on AC circuits, and don't exceed relay ratings.
To pick the right relay, calculate your load requirements. For example, switching a typical South African 230VAC, 60W light bulb:
Switching a 12V, 3A DC pump would require:
Double-check that simultaneous switching of both relays doesn't exceed the board's total current rating or supply capacity, especially with power-hungry loads.
Free shipping for orders over ZAR 1,000.00.
Get a full refund if you had the product for less than 7 days.
Nationwide delivery within 2 - 4 working days.
Communica supplies semiconductors and electronic components to industries such as automotive, electrical, automation, mining, and education.
Disclaimer: This content is for educational purposes only. Product availability, pricing, and specifications are subject to change. Always verify current details on the retailer's website before making a purchase. We may earn affiliate commissions from qualifying purchases.
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Online support and communication is next level - great communication, fast response - very helpfull, recomended supplier - online payment was no hasse...
He's polite, good with people and made me feel free to talk.. all in all he's helpful
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Best service received from Rocket! What a pleasure dealing with him. Thank you Rocket
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Excellent service so far
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Excellent service by Sydney at the ino counter. So many awsome products! Perfect place to buy gifts for tech junky friends.
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Sydney and Nicole were amazing I came in and finished within no time thank you so much keep up the friendly service
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Sydney and Nicole were absolutely fantastic and helped me with my purchases. Thank you.
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Needed to buy a bluetooth GPS receiver. The staff was friendly, knowledgeable and assisted without any issues. This is a toys tore of note for peopl...
azul and Nicole were very helpful and very efficient
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They have mostly any electronic tool and components that you may require - Thanks to Nicole for helping me.
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One of the cashier services rendered to me was here at communica by the lady named Nicole and her manager dolly they were both willing to go above and...
The service was excellent, Nicole and Rehaan were very helpful and professional in their work.
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Great service, Rehaan and Layla were spectacular with assistance. 10/10 Would definitely recommend.
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Mohamed Sharief is a great asset to Communica. He provides a 5 star service and good product knowledge. Keep up the good work.
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I received a great service from Rehaan, Windy and Nocole. Excellent customer service.
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Quick quality customer service.
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Very good service and a happy welcoming smile from the cashier Nicole
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Anyone that seriously loves technology ought to spend time here. They definitely have what you want. Best tech store!
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Verified customerNicolene
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After being supplied the incorrect track for my garage motor, despite me asking twice if it was the correct track, I had to return to the store to exc...
They have most every electronics component you might need. Staff are knowledgeable and friendly. I was looking for a bespoke miniature item for a lapt...
Great service as always from Nicole and Sydney especially Mpho at the sales desk
Verified customerGood Array of products and sound advice
Verified customerGreat inventory. Very slow service, though the staff seem to do their best. Single till open mostly with overbearing security measures. Can do with so...
I visit Communica once in a blue moon. Always wish i have more time to look at everything. Good & friendly service. Nothing wrong with a queuing syste...
Currently have only purchased items from their on-line store. Received what I ordered plus quick delivery. No complaints to date.
Verified customerThe new ticketing system is great, but the queues are still exceedingly long, and there are hardly any staff on hand in the shop to assist with questi...
I needed a heat-sensitive diode as one of my Philips appliances had had a failure. Philips wants you to throw the entire thing away, but I tried look...
I got the most pleasant service from Sydney and Windie
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Wide range of electronic components. Very likely to find what you are looking for. Arthur was very helpful. Don't bother trying to call for informatio...
Great place. Reasonable prices. Keeps component level items as well as security, surveillance and electrical items and tools
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Great pricing and a wide variety of products to choose from. A must visit if you've ever been to the Pretoria branch.
Verified customerNicole was very helpfull and friendly.
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Verified customerFor Sonoff ewelink WiFi switch.
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Verified customerClose to closing time so i was in and out quickly
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