Question: What does a negative response in superposition imply?
Answer:
A negative response implies that the original assumed direction of current or polarity of voltage should be reversed.
Showing posts with label Current. Show all posts
Showing posts with label Current. Show all posts
Saturday, May 19, 2012
Implication of a negative response in superposition
Question: What does a negative response in superposition imply?
Answer:
A negative response implies that the original assumed direction of current or polarity of voltage should be reversed.
Implication of a negative mesh current
Question: What does a negative mesh current imply?
Answer:
A negative mesh current implies that the original assumed direction of current is wrong and is in the reverse direction of the actual current.
Current for full scale deflection
Question: What current is required for full scale deflection of a galvanometer having a current sensitivity of 50 micro-amperes per scale division? The meter has exactly 50 divisions on either side of the mid-scale index.
Answer:
There are two possible interpretations of the problem. One has a meter having a mid-scale index value of zero, a maximum positive current reading, and a maximum negative current reading.
To solve for the maximum positive value of current that will cause full scale deflection, simply multiply the current sensitivity by the number of divisions. In this case, 50 micro-amperes per scale division multiplied by 50 divisions will give 2500 micro-amperes or 2.5 mA.
The other interpretation is that a meter can read from zero to a maximum positive value of current, and that there are 100 divisions in between these two extremes. In this case, 50 micro-amperes per scale division multiplied by 100 divisions will give 5000 micro-amperes or 5 mA.
Answer:
There are two possible interpretations of the problem. One has a meter having a mid-scale index value of zero, a maximum positive current reading, and a maximum negative current reading.
To solve for the maximum positive value of current that will cause full scale deflection, simply multiply the current sensitivity by the number of divisions. In this case, 50 micro-amperes per scale division multiplied by 50 divisions will give 2500 micro-amperes or 2.5 mA.
The other interpretation is that a meter can read from zero to a maximum positive value of current, and that there are 100 divisions in between these two extremes. In this case, 50 micro-amperes per scale division multiplied by 100 divisions will give 5000 micro-amperes or 5 mA.
Meter Movement
Question: Describe the type of movement used in analog meters
Answer:
The D'Arsonval movement is a DC moving coil-type movement commonly used in voltmeters, ammeters and ohm meters. An electromagnetic core is suspended between the poles of a permanent magnet as seen in the image below.
In an ammeter, current passes through the coils of the electromagnet (current path not shown in the figure). This current produces a magnetic field that opposes the magnetic field already set up by the permanent magnet in the figure. The stronger the current, the stronger the magnetic field, and the larger the pointer deflection. If current is no longer flowing, the upper and lower control springs will bring back the pointer to its default position for a zero current reading.
Answer:
The D'Arsonval movement is a DC moving coil-type movement commonly used in voltmeters, ammeters and ohm meters. An electromagnetic core is suspended between the poles of a permanent magnet as seen in the image below.
In an ammeter, current passes through the coils of the electromagnet (current path not shown in the figure). This current produces a magnetic field that opposes the magnetic field already set up by the permanent magnet in the figure. The stronger the current, the stronger the magnetic field, and the larger the pointer deflection. If current is no longer flowing, the upper and lower control springs will bring back the pointer to its default position for a zero current reading.
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