Physics Lab Equipment

LEEI-5 Construction of an Ammeter and a Voltmeter

LEEI-5 Construction of an Ammeter and a Voltmeter


  • Rich experiment content

  • Clear physical concept

  • Stable and reliable experimental result

  • Reasonable configuration


Pointer DC ammeters and voltmeters are all constructed from galvanometers. A galvanometer is usually a magneto-electric type ammeter, which only allows to flow micro-amp or milli-amp current, and can only measure very small current and voltage. In actual use, if a large current or voltage is needed to measure, the galvanometer must be modified to expand its measurement range. The modified meter should be calibrated with a standard meter and its accuracy grade should be determined.


This LEEI-5 experimental apparatus provides a complete set of components and devices for the construction of a milliamp meter or a voltmeter, including a DC power supply, a magneto-electric type microamp galvanometer, a resistance box, a digital voltmeter, a digital ammeter, and so on. It has features of rich experiment content, clear physical concept, stable and reliable experimental result, and reasonable configuration. It is suitable for teaching labs of undergraduates in colleges. 

Conducting experiments using this apparatus, students can achieve the following objectives:

1. Understand the basic structure and usage of a microamp galvanometer;

2. Learn how to extend the measurement range of a galvanometer and understand the principle of constructing a multimeter;

3. Learn the calibration method of a electric meter.

The instruction manual contains experimental configurations, principles, step-by-step instructions, and examples of experiment results. Please click Experiment Theory and Contents to find more information about this apparatus.

Main Specifications

DC power supply1.5 V and 5 V
DC microamp galvanometermeasurement range 0 ~ 100 μA, internal resistance about 1.7 kΩ, accuracy grade 1.5
Digital voltmetermeasurement range: 0 ~ 1.999 V, resolution 0.001 V

Digital ammeter

two measurement ranges:

0 ~ 1.999 mA, resolution 0.001 mA;

0 ~ 199.9 μA, resolution 0.1 μA.

Resistance boxrange 0 ~ 99999.9 Ω, resolution 0.1 Ω
Multi-turn potentiometer0 ~ 33 kΩ continuously adjustable


Configuration schematic of galvanometer



Example of experiment results

(Click figure to enlarge)

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