A digital hearing aid enhancing a directional performance for a patient who suffers from sole-ear hearing impairments is provided, in which the digital hearing aid cell inserted into one healthy ear is electrically connected with another digital hearing aid cell called an ear cell including a microphone worn in the other troubled ear, via an external electric wire. The solid-solution alloy comprises a combination of elements in specific ratios that make it magnetic resonance imaging compatible while retaining the characteristics required for implantable medical devices. Each second memory cell is used for generating a second data signal in response to a second sampling control signal, and for outputting the second data signal in response to a second transmitting control signal. The presence of the PCT pre-processed cells in the semiconductor chip layout serves to accelerate the chip-wide PCT processing of the semiconductor chip layout. A controller is configured to apply a high frequency alternating current between the monopole current injection electrode and a return and measure a corresponding AC potential difference between the first and second electrodes. The tray is kept vertical to the frames when the assembly is used as a hand truck, and is kept horizontal when the assembly is used as a stepladder and the third frame is rotated upward to support the tool tray in a high position.