EE101L - Experiment 1: Answers to Questions
Answer to Questions
1. Describe the type of meter movement used in the analog meters.
The two analog meters—namely, the voltmeter and the ammeter—employ the d' Arsonval meter movement. The movement consists essentially of a movable iron-core coil mounted on a pivot between the poles of a permanent magnet.
When current flows through the coil, it creates a torque which causes the pointer to deflect. The amount of current through the coil determines the deflection of the pointer, which is registered on a scale attached to the meter movement.
2. What device is used to extend the range of the DC ammeter and how is it connected to the basic meter?
The analog DC ammeter measures the current through a particular element and is always connected in series with it. As stated, it employs d' Arsonval movement and to allow multiple ranges of reading for specific amount of current, shunt resistors are often connected in parallel with the basic meter.
The basic meter inside an analog ammeter has an intrinsic resistance, Rm, which is essentially small enough to sanction specific amount of electric current that will cause a full-scale deflection; though most of the time it becomes inefficient in producing current reading due to excessive electric current, thus shunt resistors provide additional resistances that would complement the additional amount of current.
3. What device is used to extend the range of a DC voltmeter and how is it connected to the basic meter?
The analog DC voltmeter measures the potential difference across a certain element and must always be connected parallel to it. This device also utilizes d' Arsonval movement as discussed earlier. Analog voltmeters' basic meter has its own resistance that is large enough to allow electric current that will cause full-scale reading; and to extend the range of voltage that the meter can measure, series multiplier resistors are often connected (in series) with the voltmeter's basic meter. These additional resistances will
1. Describe the type of meter movement used in the analog meters.
The two analog meters—namely, the voltmeter and the ammeter—employ the d' Arsonval meter movement. The movement consists essentially of a movable iron-core coil mounted on a pivot between the poles of a permanent magnet.
When current flows through the coil, it creates a torque which causes the pointer to deflect. The amount of current through the coil determines the deflection of the pointer, which is registered on a scale attached to the meter movement.
2. What device is used to extend the range of the DC ammeter and how is it connected to the basic meter?
The analog DC ammeter measures the current through a particular element and is always connected in series with it. As stated, it employs d' Arsonval movement and to allow multiple ranges of reading for specific amount of current, shunt resistors are often connected in parallel with the basic meter.
The basic meter inside an analog ammeter has an intrinsic resistance, Rm, which is essentially small enough to sanction specific amount of electric current that will cause a full-scale deflection; though most of the time it becomes inefficient in producing current reading due to excessive electric current, thus shunt resistors provide additional resistances that would complement the additional amount of current.
3. What device is used to extend the range of a DC voltmeter and how is it connected to the basic meter?
The analog DC voltmeter measures the potential difference across a certain element and must always be connected parallel to it. This device also utilizes d' Arsonval movement as discussed earlier. Analog voltmeters' basic meter has its own resistance that is large enough to allow electric current that will cause full-scale reading; and to extend the range of voltage that the meter can measure, series multiplier resistors are often connected (in series) with the voltmeter's basic meter. These additional resistances will