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"Vaiseshika" Precision Vernier Potentiometer
Type : 9407 |
Description
"Vaiseshika" Precision Vernier Potentiometer Type - 9407 is designed for the measurement of voltage & current of a high order of accuracy. It can be used as a laboratory standard; for routine or accurate measurement of potential, resistance or current; as a standard for calibrationg potentiometer; for standardizing electrical currents for electrical measuring instruments; and with thermocouples etc. Excellent performance is
achieved by the use of switches throughout the measuring circuit. A main switch divides the over all potential down to 0.1 V steps and the two successive 100 way switches divide down to 0.001 V and o.oooo1 V; a range switch multiplies the range by 1, 0.1 and 0.01 when required to achieve better resolution of measurement. These 100 way switches were specially designed for the potentiometer so that thermal e.m.f's generated at the contacts are minimized with low contact resistance. More over the circuit is designed to eliminate current flow through the 100 way switch contacts at balance, thus removing any error which might arise through changes in contact resistance.
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Standardization
Standardization can be carried out independently at any time without altering the setting of measuring switches. Compensation can be made for variations in the e.m.f of the standard cell due to changes in the ambient temperature by means of a variable resistor, over the range 20 C to 40 C (e.m.f value = 1.0170 to 1.0190 volt)
After the e.m.f of the standard cell has been calculated and set on the dial, the potemtiometer may be standardized with the coarse medium and fine current controls. Three current controls are necessary, due to high resolution of the instrument.
Features
| Accurate measurement of potential, current and resistance. |
| Highest quality manganin wire well-aged standards. |
| High stepwise resolution of 2microvolt at the last range switch setting. |
| Excellent Accuracy of ± 0.005. |
| mpeccable craftsmanship in construction, rigorous testing and simplicity of operation |
| Hard silver plated,
self-cleaning switches with minimum contact resistance
errors |
Specification
| Range of Measurement: 0 to 1.90100 volt. |
| Range |
Range switch setting |
| 0 micro V to 1.90100V |
: X1 |
| 0 micro V to 0.190100V |
: X0.1 |
| 0 micro V to 0.0190100V |
: X0.01 |
| Range |
1st switch |
in steps of |
2nd switch |
in steps of |
3rd switch |
in steps of |
| X1 |
: 0 to 1.8V |
: 0.1V |
: 0 to 0.1V |
: 1mv |
: 0 to 1mV |
: 10microV |
| X0.1 |
: 0 to 0.18V |
: 10mV |
: 0 to 10mV |
: 100 micro v |
: 0 to 100microV |
: 1microV |
| X0.01 |
: 0 to 0.018V |
: 1mV |
: 0 to 1mV |
: 10 micro v |
: 0 to 10microV |
: 0.1microV |
| Weight (in Kg) |
: 9.5 (approx.) |
| Dimensions (in mm) |
: 610(L) x 350(B) x 193(H) approx |
| Internal Resistance |
: 100 ohms per volt |
| Range of Measurement |
: 0 to 1.90100 volt |
| Measurement Accuracy |
: 100 mV to 1.9 V + 0.005%
: 1 mV to 99 mV + 0.01%
: up to 0.9 mV + 0.05% |
or +/- 5 scale division which ever is greater |
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Spot Reflecting Galvanometer Type 9407A (Essential Assessory)
The Spot Reflecting Galvanometer will serve as a null detector to obtain the balance point in the circuit. The instrument is housed in a black bakelite case with lamp and scale arrangement for providing moving spot on the calibrated scale. The galvanometer resistance is of the order of125 ohms. The critical damping resistance will be1000 ohms and the galvanometer will be working on 220 volt AC
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VOLT RATIO BOX TYPE 9407B
(Essential Accessory)
The Volt Ratio Box is required if the voltage to be measured is above 2 volts. The Volt Ratio Box consists of a high resistance of the order of 37.5 K ohms having a number of tappings, the resistance between the various pair of tappings being carefully adjusted
.
Range for voltage 1.5, 15, 30, 150 and 750 Volts.
Resistance 37.5 K
Accuracy ± 0.05%
The Volt Ratio Box employs high stability and low temperature co-efficient manganin coils which gives remarkably stable readings over varied range of voltages. The coils are having long ageing and have been subjected to vacuum impregnation to avoid any damage to the measuring accuracy due to moisture, corrosion or salt conditions prevailing in the measuring area.
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ELECTRONIC 2 VOLT ACCUMULATOR (DC SOURCE) TYPE 9407C
(Essential Accessory)
This accumulator delivers 2 Volt, 500 mA stabilized DC regulated power supply. The electronic unit is having low ripple content and employs solid state circuitry using LSI/MSI circuits and TTL components.
Two terminals are given at the front panel to deliver the constant voltage. The unit is used to energize potentiometers during working.
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STANDARD CELL DC TYPE 9407 D
(Essential Accessory)
The Standard Cell is used in the Potentiometers to calibrate a potentiometer against a standard and stable DC volt signal varying from 1.0185 to depending upon the ambient temperature with variation of 40mV/°C. Suitable compensations are provided in each Potentiometer to take account of the variation in the value of the DC voltage obtainable from the Standard Cell. One Standard Cell is required with one Potentiometer. It is essentially a calibration reference standard for the Potentiometer and thus a part and parcel of the support accessories system of the Potentiometer.
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DECADE RESISTANCE BOX TYPE 7400
(Optional Accessory)
The Standard Decade Resistance Box Type 7400 is used to calibrate current and volt meters with the help of Potentiometer. The range of the Resistance Box is from 0.01 ohm to 100 K having decade steps from 0.01 ohm to 10 K ohm. The Box employs manganin coil to provide high stability to the resistance values having accuracy of 0.05%. |
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