CET Test Equipment and Measurements 2

Question 1

On an oscilloscope, the timebase (horizontal axis) represents:

Accepted Answer

Time in seconds per division

Answer

The horizontal (X) axis of an oscilloscope is the timebase, calibrated in time units (seconds, ms, or µs) per division.

Question 2

What is the typical input impedance of a standard 1X oscilloscope probe?

Accepted Answer

1 megohm

Answer

A standard 1X probe presents 1 megohm of input impedance to minimize circuit loading during measurements.

Question 3

If a 10X oscilloscope probe is used and the scope display reads 5V, what is the actual signal voltage?

Accepted Answer

50V

Answer

A 10X probe attenuates the signal tenfold before the scope input, so the actual voltage is 10 times the displayed value: 5V × 10 = 50V.

Question 4

A decibel (dB) measurement expresses:

Accepted Answer

A logarithmic ratio between two power or voltage levels

Answer

The decibel is a dimensionless logarithmic ratio comparing two power or voltage levels, not an absolute quantity.

Question 5

What power level does 0 dBm represent?

Accepted Answer

1 mW

Answer

0 dBm is defined as a power of 1 milliwatt; it is the 0 dB reference point on the dBm scale.

(CET) Certified Electronics Technician Practice Test