OSCILLOSCOPE

Typical Number in Hospital: 4

Cost Bands: 3,4

References: 3

This is an instrument containing a cathode ray tube (CRT) intended for viewing signals that vary with time. There are different types of oscilloscope but the most common format is a short-persistence CRT with amplifiers driving the vertical (Y) deflection plates and a time base driving the horizontal (X) deflection plates. The amplifiers usually have variable gain and sometimes filtering circuits; the time base allows the horizontal sweep of the spot to be made at different speeds. Other variations are to have a storage CRT or electronic storage circuits, X and Y drive amplifiers (i.e. no time base), differential amplifiers, special time base triggering circuits, etc.

General-purpose oscilloscopes are only found in electronics research or servicing laboratories; however, the common cardioscope is in fact an oscilloscope with a time-base, a differential amplifier with filters, and a long-persistence CRT or memory circuit. However, one does not usually think of them as oscilloscopes.

Because of their versatility, it is often convenient to use an industrial oscilloscope as the display for a medical measuring instrument. In these circumstances care should be taken to ensure there is no breach of the recommendations relating to the use of electrical equipment in the patient environment.