Ultrasonic Cleaning

A method of cleaning delicate or intricately structured items (such as dentures, contact lenses, or jewelry) in which the soiled items are immersed in a fluid that is agitated by ultrasonic transducers; the foreign particles are shaken away.

Ultrasonic Level Detector

A level-monitoring system in which an ultrasonic transmitter and detector are mounted together on one wall of a tank or chamber. When the tank is empty, the transmitted signal is reflected by the opposite wall back to the detector. When the liquid rises, the reflection time is reduced; this change is used to operate a device that indicates that the tank has been filled to a desired level.

Unbalanced Line

1. A transmission line in which one side (conductor) is grounded (e.g., a coaxial line). 2. A normally balanced transmission line in which the currents in the two halves are out of balance (i.e., they are not equal in amplitude and opposite in phase).

Unbypassed Emitter Resistor

In a common-emitter transistor circuit, an emitter resistor without a bypass capacitor. The flow of output-signal current through the resistor produces negative feedback within a single stage.