Kelvin Double Bridge Laboratory Equipments Supplies

a) Multiplying Ratio :- A rotary switch furnishes 5 multiplying ratios of x 100, x10, x1, x0.1 and x0.01. b) Range of Measurement :- The bridge had a range of 0.2 micro ohm to 11 ohms. c) Maximum Current :- 10 amperes intermittently and 5 amperes continuously. d) Resistance Coils :- Manganin coils are used. e) Terminal :- Terminals for battery, galvanometer current and potential terminals are all provided on the backelite panel enclosed in a teak wood box. f) Current Reversing Switch : A battery reversing switch is provided to reverse the current in the bridge to eliminate thermal effects. g) Accuracy :- 0.5% + 1 small division of the slide wire. h) Industrial Kelvin Double Bridge :- The above bridge can be supplied with an additional range factor of x 1000 to give the range of measurement as 0.2 micro ohms to 110 ohms at extra cost. i) Adjustable Heavy Duty D.C. Current source :- It is a useful and economical substitute for a D.C. battery. The unit is mains operated and can deliver a continuously adjustable D.C. current of 0 to 10 amperes maximum. The unit consists of a variac, a step down transformer. A bridge rectifier, filter circuit and an ammeter of 0 to 10 amperes to read current. Input Voltage :- 230 volts A.C. Mains at 50C/s. D.C. Output : Approximately 0 to 10 volts continuously adjustable to give a variable current of 0 to 10 amperes depending upon external lead. j) Conductivity Attachment:- It is an arrangement to hold specimens in the form of wires, rods, strips etc. Separate current and potential terminals are provided. Distance between potential points is 500 mms it can hold specimens of any size between ½” dia rod to 42 S.W.G. wires. k) Potentiometer Shunts :- These are precision shunts suitable for calibration of Ammeters etc. with the help of D.C. Potentiometer. These shunts are provided with 4 terminals (current and potential), They can be supplied with standard milli volt drop of 75 milli volts. Resistance in ohms  a) 0.005 b) 0.0025 c) 0.001 d) 0.005