Post Office Box (PO Box) for Physics Practical Classes & Exams

This plug-in-type post office box physics is designed for accurate electrical experiments in physics practicals and exams. It features heavy brass contact blocks securely fixed to a vulcanite plate using a double nut system. The plugs and lugs are finely tapered for interchangeability, and the plug heads are machine-molded from durable Bakelite.

Each resistor is independently mounted with double leads for reliability. High-precision Constantan coils ensure an accuracy of ±0.1% for lower values and ±0.5% for higher values. The resistors use premium imported constant wire wound on ebonite spools using a non-inductive, non-magnetic method and are sealed in boiling wax for durability.

Key features of PO Box:

• Three ratio coils: 1000Ω, 100Ω, and 10Ω
• Rheostat arm: 15,000Ω
• Two tapping keys with silver contacts for battery and galvanometer connections
• Enclosed in a sturdy teakwood case with a hinged lid
• Dimensions: Approx. 280 x 200 x 175 mm
• Made in Bangladesh

Note: Product color and size may slightly vary from the image.