An ideal diode is one kind of an electrical component that performs like an ideal conductor when voltage is applied in forward bias and like an ideal insulator when the voltage is applied in reverse bias. So when +ve voltage is applied across the anode toward the cathode, the diode performs forward current immediately. When a voltage is applied in reverse bias, then ir performs no current at all. This diode operates like a switch. When the diode is in forward bias, it works like a closed switch. Whereas, if an ideal diode is in reverse bias, then it works like an open switch.