State the advantages and disadvantages of DMM.
Answers
the pros or advantages of digital multimeters.
They are more accurate than analog multimeters.
They reduce reading and interpolation errors.
The 'auto-polarity' function can prevent problems from connecting the meter to a test circuit with the wrong polarity.
Parallax errors are eliminated. If the pointer of an analog multimeter is viewed from a different angle, you will see a different value. This is parallax error. A digital multimeter's numerical display solves this problem
Digital multimeter displays have no moving parts. This makes them free from wear and shock failures.
The reading speed is increased as it is easier to read.
Unlike analog multimeters, zero adjustment is not required.
Digital output is suitable for further processing or recording and can be useful in a rapidly increasing range of computer controlled applications.
With the advent of Integrated circuits, the size, cost and power requirements of digital multimeters has been drastically reduced.
Accuracy is increased due to digital readout. You can make mistake in reading the scale in analog multimeter, but digital multimeters have a LCD display to show accurate reading.
Disadvantages of Digital Multimeters
The LCD display depends on a battery or external power source. When the battery is low, the display will be dim, making it difficult to read.
In case of fluctuations or transients, it can record an error.
Warming of the meter during its use can change its properties leading to errors in measured value.
The A/D converter has a limitation on word length which can cause quantization noise giving rise to error in measured value.
There is a voltage limitation. If it is increased beyond the limit, the meter will be damaged.
The digital nature makes it unsuitable for adjusting tuning circuits or peaking tunable responses.
They are expensive due to high manufacturing cost.