Pencil Jockey (Knife Edge Jockey) Manufacturer,Supplier and Exporter in India

Pencil Jockey (Knife Edge Jockey) (Product Code: SLE/EM/24) is the sliding contact used to locate balance points on Wheatstone bridges and potentiometers: a brass knife edge at one end of an insulated, pencil-style handle, with a 4mm socket binding post terminal at the other. At 100mm overall it sits comfortably in one hand during senior-secondary and undergraduate practicals, and it is a standard companion to meter bridge and potentiometer lab work across India. It is made by Jain Scientific Equipments Pvt Ltd (ScienceLab), Ambala, India.

Specifications

Typical Use

In a meter bridge or slide-wire Wheatstone bridge experiment, the jockey is connected through a galvanometer and touched at points along the bridge wire until the galvanometer shows no deflection; the balancing length then gives the unknown resistance. In a potentiometer experiment the same null method is used to compare the emfs of two cells or to find a cell’s internal resistance. Because the knife edge meets the wire along a narrow line, the balance point can be read closely against the scale — the reason a knife-edge jockey is preferred over a blunt contact in these experiments.

Press the jockey gently and lift it before moving to a new point. Dragging the edge along the wire scrapes it and changes its resistance per unit length, which spoils later readings. Run the lead from the 4mm socket to the galvanometer, keep the brass edge clean and straight, and store the jockey where the edge will not be knocked.

Manufacturer

The Pencil Jockey is made by Jain Scientific Equipments Private Limited, which trades as ScienceLab from Ambala, Haryana. The company is a registered MSME enterprise (Udyam UDYAM-HR-01-0003714), and its export orders are shipped under Importer-Exporter Code AAECJ8618A issued by the DGFT. Read more on our company profile.

Related Laboratory Equipment

Apparatus the jockey is used with in null-method experiments:

• Meter Bridge — the slide-wire bridge for finding unknown resistance
• Wheatstone Bridge Four Gap — a four-gap bridge for resistance comparison
• Potentiometer — for emf comparison and internal-resistance experiments
• Galvanometer, Centre Zero Universal Meter — the null detector connected in series with the jockey
• Jockey with Insulated Handle (Single) — an alternative jockey style in our physics range

Find more in our Electricity Equipments category.

Frequently Asked Questions

Which instruments is this jockey meant for?
Wheatstone bridges (including meter bridges) and potentiometers, where it is used to find the null or balance point on the wire.

How is it connected to the circuit?
Through the 4mm socket binding post terminal at the end of the handle, so a lead with a 4mm plug or a bare wire can be used.

How long is it?
100mm overall.

Why a knife edge rather than a rounded tip?
A knife edge touches the wire along a narrow line, which makes the balance point easier to locate and read precisely.

How do I avoid damaging the bridge wire?
Tap the jockey on and off the wire instead of sliding it while pressed, and use light pressure.

Can you supply jockeys in bulk or for export?
Yes. We supply schools, colleges and distributors in India and international markets; include quantity and destination in your enquiry.

Request a Quote

For a quotation, contact us or add the Pencil Jockey to the enquiry cart with your bridge and potentiometer requirements.

Last updated: 24 September 2026