Single-channel relay module is an electronic component that allows a low-power control signal (from a microcontroller like an Arduino, Raspberry Pi, ESP8266, or ESP32) to switch a high-power device (like a light bulb, motor, or other appliances) on and off.
Single-channel: Controls one relay switch.
Voltage Options: Typically 5V, 12V, or 24V relay modules.
Relay Ratings: Usually support AC (e.g., 250V 10A) and DC (e.g., 30V 10A).
Optocoupler Isolation: Provides electrical isolation between the control circuit and the relay.
Trigger Type: Low-level or high-level trigger selection.
LED Indicators: Power and relay status indicators.
Wiring:
Input Pins (Control Side - Low Voltage)
VCC: Power supply (5V/12V/24V depending on the module)
GND: Ground connection
IN: Control signal (HIGH activates relay, LOW deactivates it)
Output Pins (Load Side - High Voltage)
COM (Common): Common terminal
NO (Normally Open): Default open circuit, closes when relay is activated
NC (Normally Closed): Default closed circuit, opens when relay is activated
Applications:
Home automation
Motor control
Light switching
Smart IoT projects