Bridge R329 (P 329, P-329, r329, P 329, P-329)
Bridge R329 - five decade box a single-double bridge, designed for accurate measurement of resistance.
Class of accuracy:
- Double Bridge: 1.5, 0.5, 0.1, 0.05,
- Single axle: 0.05, 0.5.
- Double Bridge: 0.000001 ohm - 0.00001 ohms 0.000010001 Ohm - 0.0001 ohms 0.00010001 ohms - 0,001 ohms, 0010001Om - 100.0 ohms;
- Single Drive: 50Om - 100000Om; 100010Om - 111110Om.
Structural features of R329
R329 bridges are made of separate units, mounted on cast Silumin board, which is set in the village evyannom housing.Overall housing measures just 520 × 330 × 240mm.Decadal panel switches and socket pads are made of plastic. To protect it from contamination dnye deck switches with plastic caps secured to the switch panel.
All resistance R329, except the youngest decade resistance and resistance 0.001 ohm resistors built-in power model, implemented on a porcelain x frames.Resistance About 0,001 m made of sheet manganin (flax you).Block model of resistance tions are removable and interchangeable fired.Tion resistance unit can be used as an independent ITATION exemplary resistance class 0.02.Each bridge I are applied five flexible wires resistance ≤ 0,001 ohms each and a special shoe with two double clamps to measure short wire resistances.All measurement of resistance of the bridge can be verified element by element, for which the contacts of switches and sockets are special to (the device comes with two flexible conductors, each with a tip and a plug.
Bridge R329 - combined, the same decade of resistance, and resistance measurement are used to construct a scheme of single axle and dual-bridge circuit.Comparative plait chi bridge R 1 and R '1 have one hundred five decades 10 × 100 10 × 10, 10×1 10× 0,1× 0,01 and 10 ohms, which allows the resistance of the comparative sample arm with an accuracy of ± reference 0.0005%. Every decade for the fit and comfort, and a chip unit verification is the total number of resistors with nominal values that are multiples of 10.No resistance reference leg does not exceed 0,005 ohms. A variation of this resistance is not more than 0.0005 ohms.
The first stage of the younger decades reference leg is fitted with the zero resistance, which further increases the accuracy of measurements on the bridge.
Comparative shoulder R 1 is used in the schemes of single and double bridges, shoulder R '1 - but in the scheme of the double bridge.Resistance shoulders relations R 2 and R 3 have the same value at 10 Ohm, 100 ohms, and 1000Om 10000Om.
Block resistance is only exemplary in double bridge circuit for measuring resistivity by maloomnyh chetyrehzazhimnoy connection circuit. Shema bridge allows for measurements of resistance maloomnyh use either built-in or external exemplary resistance.
Measuring the resistance of 10 ohms to 100 ohms -6 using the built-resistance model is as follows BrAZ.Current clamp measured resistance R x is connected to the terminal T 1 of the model resistivity copper jumper impedance of 0,001 ohms with carefully stripped ends.The potential of a conductor measured resistance connected to the terminals of a X in the correct polarity, resistance to them should also be no more than 0,001 ohms.
Recommended values of the resistance arms that have bridges R329, the maximum current through the exemplary resistance, as well as the parameters galvanometer for high accuracy measurements using all five decades of the comparative arm are summarized in Table 1.
Balancing by changing the resistance of the paired decades of R 1 and R '1. Measured resistance tion is given by:
where R 1 - reading on the limbs of switches;
R 2 - PLUG-reading on the shoulder;
R N - The value of a model of resistance.
Recommended values of the resistance arm of the bridge R329 and parameters for measuring the resistance of the galvanometer of 10 -6 ohm to 100 ohms using external resistors model are shown in Table 2.
Current supply circuit is established on the ammeter with the maximum value of the current model for the resistance.
Measurement of resistivity of from 50 to 10 6 ohms produced by single bridge circuit without the use of raztsovyh resistances.In this case, the terminals + N and-N are shorted flitches from block resistance model.Sensing of resistance is connected to the terminals of the bridge X 0, the power supply - to the terminals B.
Recommended values of resistors R329 shoulder bridges, power supply voltage and the parameters of the galvanometer, providing high accuracy by using all five decades of the comparative arm are shown in Table 3.
The measured resistance is calculated by the formula
where R 1 - reading on the limbs switches shoulder comparison;
R 2 and R 3 - readings on the plug shoulders.
Resistance Measurement of short lengths of wires and tapes and mass adjustment and calibration of resistance coils can be produced using a special pad with double clamps. The measurement is performed in a double bridge. Block its potential ends is connected to the terminals of a X Bridge.Current terminals include pads prepared in the scheme, depending on external or integrated with an exemplary impedance measurements are performed.
Comparative shoulders bridge R329 R 1 and R '1 may be used as pyatidekadnyh stores, each of which produces an alternating action class value of 100 ohms to 0.02 ohms 1111.11 steps of 0.01 ohms with an error of ± (0,015 + 0,05 m / R)%, where:
m - number of decades, the indications are not equal to zero;
R - value dialed resistance in ohms.
Thus both stores can work simultaneously in various electrical circuits.
Stores can R329 connected in series, and the resistance will vary from 0.02 to 2222.22 0.02 ohm steps ohms. The current through the resistance decades shop shall not exceed: for the first ten days - 0.02 A for the second - 0,2 A for the third - 0.5 A, for the fourth and fifth - 1A.
The maximum voltage drop at the terminals of the store with a fully introduced resistances shall not exceed 22V.
Zero indicator (galvanometer) is connected to the terminals of G. Sensitivity adjustment is carried out by using the coarse and fine. When including chenii roughly consistent with the null indicator turns 50kOm resistance. When you turn on button ki accurate indicator included in the scheme but directly.Calming the galvanometer with a key Consolation. Impedance 10 ohm shunt galvanometer and resistance in the circuit 50Om Consolation give the opportunity to work galvanometer (as mnogoomnomu and maloomnomu) in near-critical, for the closure of roughly button.
Photos: R329 (P329)