Assuming you have successfully installed the library, here is a practical simulation scenario:

// Turn on the motor relayTurnOn(RELAY_PIN, CHANNEL_1);

: Includes built-in models for optocouplers (like the PC817) for isolation, driving transistors (like the 2N2222), and flyback diodes (like the 1N4007) for back-EMF protection.

The downloaded library might be a "black box." To truly understand and trust your simulation, you should know what is inside a good 4 Channel Relay Module library.

.MODEL RelayChannel (SWITCH) + RON=0.1 + ROFF=1e6 + VT=2.5 ; Threshold voltage for activation + VH=0.5 ; Hysteresis