1 Channel Relay - 5V

Specifications

• Operating Voltage (VCC): 5V DC
• Trigger Current: 15mA - 20mA per channel
• Relay Contact Capacity (AC): Up to 250V @ 10A
• Relay Contact Capacity (DC): Up to 30V @ 10A
• Logic Compatibility: Standard TTL Level (AVR, Arduino, 8051, PIC, ARM)
• Output Contacts: 1x Normally Open (NO), 1x Normally Closed (NC), 1x Common (COM)
• Protection: Built-in triode drive for coil amplification and pull-down circuit to avoid malfunction on power-up.
• Indicators: Dedicated onboard LEDs for Power Supply (VCC) and Relay Status (Action).

Applications

• IoT Smart Plugs: Build custom Wi-Fi controlled power outlets using an ESP8266/ESP32 (with logic level shifting).
• Home Automation: Safely switch on room lights, ceiling fans, or exhaust systems via Arduino.
• Automated Gardening: Control 12V DC solenoid valves or water pumps based on soil moisture data.
• Industrial Prototyping: Interface low-voltage PLCs or custom controllers with factory warning lights or contactors.

Unlock New Capabilities

• The Starting Point: If you've mastered blinking small 5mm LEDs or reading temperature sensors, you are currently limited to low-voltage, low-current hardware.
• The Upgrade: This relay module unlocks high-power control. You are no longer restricted to 5V; you can now write code that turns on a 220V desk lamp, a heavy 12V geared motor, or a loud siren.
• Effort Level: Beginner. You only need basic jumper wires, a standard 5V microcontroller, and an understanding of basic digital write (HIGH/LOW) commands.

Virtual Technician & Wiring Guide

• ⚠️ SAFETY WARNING: This module can handle lethal mains voltage (110V/220V AC). Always ensure your circuit is completely disconnected from wall power before touching the screw terminals. If you are inexperienced with AC mains, stick to switching low-voltage DC (like 12V batteries) until you are confident.

Microcontroller Wiring:

• VCC: Connect to the 5V pin on your Arduino/Microcontroller.
• GND: Connect to the common Ground (GND).
• IN: Connect to any Digital I/O pin (e.g., Pin 8). Setting this pin HIGH or LOW (depending on active state) will click the relay.

Load Wiring (Screw Terminals):

• COM (Common): Connect your live power source here (e.g., the positive wire from a 12V battery, or the Live wire from an AC plug).
• NO (Normally Open): Connect to your appliance. The appliance will stay OFF until the relay is triggered.
• NC (Normally Closed): Connect to your appliance. The appliance will stay ON, and will turn OFF when the relay is triggered.

Package Includes:

• 1 x 1 Channel Relay - 5V

Frequently Asked Questions (Technical FAQs)

• How much current does the 'IN' trigger pin draw from my Arduino?
  The trigger pin only draws about 15mA to 20mA, which is well within the safe 40mA limit of a standard Arduino digital pin.
• Can I use this relay directly with a 3.3V microcontroller like an ESP32 or Raspberry Pi?
  The relay coil requires 5V to switch mechanically. While a 3.3V logic signal might trigger the input pin, it is highly recommended to supply 5V to VCC and use a logic level converter or a transistor for the trigger pin to ensure reliable operation.
• Will this relay module work for PWM (Pulse Width Modulation) dimming?
  No. Mechanical relays physically move a metal contact. Using PWM will cause the relay to chatter violently, rapidly destroying the mechanical contacts. Use a Solid State Relay (SSR) or MOSFET for PWM.
• What happens if my Arduino loses power?
  If the logic signal and 5V power drop, the relay will return to its default resting state. The NO (Normally Open) circuit will break, and the NC (Normally Closed) circuit will connect.
• Why is my relay clicking, but my 12V motor isn't turning on?
  Ensure your load is wired in series with the COM and NO terminals, not in parallel. The relay acts as a switch, it does not supply power to the load terminals itself.
• Do I need to add an external flyback diode?
  No, this module includes a built-in drive and protection circuitry to handle the coil's back-EMF, protecting your microcontroller.
• Can I switch a 1.5HP water pump with this relay?
  No. While rated for 10A, inductive loads (like large AC motors/pumps) draw massive surge currents on startup that will fuse the contacts. Use this relay to trigger a heavier industrial contactor instead.
• What do the two onboard LEDs mean?
  The Power LED indicates the board is receiving 5V on VCC/GND. The Action/Status LED illuminates when the trigger pin receives a valid signal and the coil is energized.
• Is this relay active HIGH or active LOW?
  Standard 1-channel modules are typically Active High (sending a 5V HIGH signal triggers the relay). However, always test with your specific batch, as some board revisions utilize an active LOW trigger.
• Can I control a 12V LED strip with this?
  Yes, as long as the total current draw of the LED strip does not exceed 10A at 12V DC.
• Why does my Arduino reset every time the relay clicks?
  This is usually caused by electromagnetic interference (EMI) or a voltage drop if the relay coil and the Arduino share a weak power supply. Power the relay from a separate 5V source, or ensure your power supply has sufficient current overhead.
• What is the maximum switching speed of the relay?
  Mechanical relays are slow. Expect a switching time of around 10-15 milliseconds. Do not attempt to switch it faster than a few times per second.
• Does this module provide full opto-isolation?
  This specific basic 1-channel board relies on a triode drive circuit for separation. If your project requires true optical isolation for extreme electrical noise environments, consider an Opto-Isolated Relay Module.
• Can I connect the Ground of my 220V AC circuit to the Ground of the Arduino?
  Absolutely NOT. AC mains wiring must remain completely isolated on the screw terminal side. Never mix the low-voltage DC ground with high-voltage AC lines.
• How long will the relay contacts last?
  Under normal rated loads, mechanical relays are rated for roughly 100,000 electrical operations.
• I wired my lights to NC, why are they always on?
  NC stands for Normally Closed. It completes the circuit by default when the relay is off. If you want the lights off until you trigger them, move the wire to the NO (Normally Open) terminal.
• Can I use a 9V battery to power the VCC pin?
  No, applying 9V to the VCC pin will burn out the relay coil and the onboard drive circuitry. Use a regulated 5V source.