Portable Wheatstone Bridge Apparatus Circuit Board

Product Code : SCL-EAE-12041

Portable Wheatstone Bridge Apparatus Circuit Board (SKU SCL-EAE-12041) is a self-contained four-arm bridge with a built-in centre-zero galvanometer, ratio switch and battery compartment, used to find an unknown resistance by the null deflection method. It is meant for physics classrooms and electrical engineering students. Science Lab Supplies manufactures the board at its own factory at Plot 448, HSIIDC Industrial Area, Saha, Ambala, India, and sells it directly to schools, colleges, tender contractors and distributors.

Specifications

Every technical detail of the board is listed in the table below. In short, it combines a classic four-arm bridge, a ±30 µA centre-zero galvanometer protected by push-button shunt switches, a rotary ratio switch from x0.01 to x1000 and a 9 V battery compartment, and it measures from 1 Ω to 10 MΩ.

Applications and Experiments for the Portable Wheatstone Bridge

The board is used to measure unknown resistances by balancing the bridge and to show why no current flows through the galvanometer at balance. It fits current-electricity practicals in Class 12, B.Sc. physics and first-year engineering, giving each group a compact piece of school physics lab equipment in India in place of loose boxes and leads.

• Class 12 physics (NCERT current electricity): verifying the balance condition P/Q = R/X and comparing the result with a slide-wire Meter Bridge or Wheatstone Bridge With Pencil Jockey.
• B.Sc. and diploma practicals: measuring resistors from 1 Ω to 10 MΩ by changing the ratio arm, then cross-checking a value on a Digital Ohmmeter (20 kΩ).
• Comparing the board with the Post Office Box Plug Type, which uses plug-in ratio arms and spring keys.

Standard Scope of Supply

Each kit contains the bridge board main unit, a set of encapsulated test resistors for practice, ten multi-coloured stackable 4 mm banana patch cords and an English guide with step-by-step experiment setups. A 9 V battery is not part of the listed contents and can be added to the quotation.

Packing, MOQ and Lead Time

A quotation can cover one board for a teacher demonstration or a set for every bench in a current-electricity practical. Science Lab Supplies states the packing, delivery time and price for the quantity you request, and resistance boxes or galvanometers can be listed on the same quotation.

With an Importer-Exporter Code in place, Science Lab Supplies is able to ship to buyers in Saudi Arabia, Oman, the Philippines, Nepal, Bangladesh and Zambia. Send your list via the contact page or enquiry cart; tender requests are covered on the lab tender page.

Frequently Asked Questions

How does the board find an unknown resistance?
The resistor goes into the X arm, and the ratio switch and standard dials are adjusted until the centre-zero galvanometer reads zero. The unknown value then follows from P/Q = R/X, since no galvanometer current flows at balance.

What resistance range does it cover?
The rotary ratio switch has six settings from x0.01 to x1000. Together with the built-in standard arms, they cover unknown resistances from 1 Ω up to 10 MΩ on one board.

Is the galvanometer protected during balancing?
Yes. Push-button shunt switches limit the current through the ±30 µA centre-zero meter while the bridge is far from balance. Hold the coarse button while adjusting, then fine-tune the dials for the null.

Does Science Lab Supplies make this board itself?
Yes. As a science apparatus manufacturer in India, Science Lab Supplies assembles the bridge board at its own factory in Saha, Ambala, so school, tender and distributor quotations come straight from the production unit rather than a trading company.

Related Resistance Measurement Apparatus

These items from the Electrical and Electronics and Lab Meters ranges cover the other classic ways of measuring and setting resistance, plus the keys and meters used beside them, so a complete current-electricity bench can go on one quotation with the bridge board.

• Resistance Box Plug Type (Constantan / Manganin Coil) — constantan or manganin coils on bakelite spools in a wooden case.
• Decade Resistance Box, Dial Type — 1 percent metal film elements in series-connected dials, for AC or DC.
• Potentiometer with Jockey Pencil — brass blocks, 4 mm sockets, a 100 cm scale and a knife-edge jockey.
• Laboratory Spot Reflecting Galvanometer — detects small currents through a reflected light-spot indication.
• Tapping Key Physics Lab — momentary key rated 24 V DC and 2 A, with 4 mm binding posts.
• Ohms Law kit Apparatus — built-in 0–12 V regulated DC supply with dual-range meters.

Browse the full Electrical and Electronics range, the Lab Meters range, or all physics lab equipment.

Last updated: 9 October 2026