Shown on this slide is a simplified block diagram of the key systems in a washing machine using a traditional relay disconnect. The washing machine is turned on and off by a switch which can bypass the AC power relay and connect the internal circuitry to the AC source. When the wake-up switch is pressed, power passes through the EMI filter to the auxiliary supply which starts up and powers the microcontroller. The controller then switches the main AC relay, latching the entire system on. There are some challenges to this traditional approach, including the cost of the high-voltage AC switch and relay circuit. Also, there is a significant amount of wiring needed to connect the AC input, typically located in the bottom rear of the unit, with the high-voltage circuitry which must be placed at the top front. This length of wire not only costs more, it also causes problems for EMI filter placement. In this diagram, the EMI filter is shown in its ideal location for minimal standby losses, which is after the input relay. But, for an EMI filter to be most effective, it must be as close to the AC input cable as possible. This means that the EMI filter must often be placed before the input relay, causing it to present a continuous load on the AC supply, increasing standby losses. This is why even relay-based designs often fail to achieve zero power consumption in standby.