Post Office Box Dial Type

Post Office Box Dial Type

Post Office Box Dial Type – Physics Laboratory Instrument

• Post office box is constant coils.
• 6 dial each consisting of 10 steps.
• Provided with four ratios of 1, 10, 100, 1000 ohms and 2 ratios dials.
• And then with Manganian coils 5 dials.
• Plug type, in polished wooden box with hinged lid and panel to show circuit connections.
• Coils of constantan wire double silk covered are wound non- inductively. Three pairs of ratio arms are each 10, 100, 1000 ohms and resistance arms contains 16 coils from 1 to 5000 ohms with infinity plug.
• Total value 11, 110 ohms.
• Two spring keys having contact for battery and galvanometer fitted.
• Accuracy of coils 100 to 500 ohms + 0.05% and of the rest coils + 0.1%.

Available in coils –

• 4 dials , Constant coils
• 4 dials , Manganian coils

Features:

• Precise design 
• Simple usage 
• Resistant against rus