Ultrasound technicians may expect to perform some of their work in rooms with low lighting. They can expect to be on their feet for a majority of their work time, and must be able to do some lifting or turning of patients who require assistance.
semiconductor diode A diode made of semiconductor components, usually silicon. The cathode, which is negatively charged and has an excess of electrons, is placed adjacent to the anode, which has an inherently positive charge, carrying an excess of holes. At this junction a depletion region forms, with neither holes nor electrons.
What is a light-emitting diode? A diode is a two-terminal semiconductor device. It can be thought of as an electronic valve that only allows current to flow in one direction. The symbol for the diode is shown in the lefthand picture of figure 5. The symbol is shaped like an arrow that indicates the direction in which current may flow. The terminal marked with a positive sign is called the anode and the terminal marked with a negative sign is called the cathode. The righthand picture depicts the physical device.