Electric, such as the H11L1, are electrical components designed to provide electrical isolation between two parts of a circuit. The H11L1 contains an infrared LED and a photosensitive transistor as the two parts of its optical coupling circuit.The H11L1 utilizes a logic input and output and provides both power and signal isolation. It can be used to convert TTL (Transistor-Transistor Logic) or other compatible low voltage logic signals to a higher voltage logic level. This allows signals to be transmitted through the optocoupler while isolating the input and output circuits from each other. The H11L1 can also be used to control low power AC or DC circuits. It works by turning on or off the LED with a logic input signal, which then triggers the photosensitive transistor. The transistor then turns the circuit on or off according to the input signal.