CET CET Equipment Operation and Maintenance

Question 1

What does the standard paper speed setting of 25 mm/sec mean on an EKG tracing?

Accepted Answer

Each small box represents 0.04 seconds horizontally

Answer

At 25 mm/sec, each 1 mm small box on the horizontal axis equals 0.04 seconds of time.

Question 2

What is the standard voltage calibration for a clinical EKG machine?

Accepted Answer

10 mm/mV

Answer

Standard EKG calibration is 10 mm/mV, meaning a 1 mV signal produces a 10 mm deflection on the paper.

Question 3

A calibration pulse at the start of an EKG tracing appears shorter than expected (5 mm instead of 10 mm). This indicates the machine is set to:

Accepted Answer

Half standard (5 mm/mV)

Answer

A 5 mm calibration pulse indicates the machine is set to half standard, which is used when large-amplitude waveforms extend off the paper.

Question 4

What is the primary purpose of the filter settings (e.g., 40 Hz, 150 Hz) on a modern EKG machine?

Accepted Answer

To reduce electrical artifact and noise without distorting cardiac waveforms

Answer

Filters attenuate high-frequency or low-frequency noise (such as muscle artifact or AC interference) while preserving the diagnostic waveform shape.

Question 5

Which lead wire color corresponds to the right arm (RA) electrode in the American (AHA) color-coding system?

Accepted Answer

White

Answer

In the AHA system used in the US, white identifies the right arm lead wire.

(CET) Certified EKG Technician Practice Test