How to Make a Cheap Amp Meter

Amp meters test the current of amps running through a shunt.

An amp meter or ammeter is connected in series to a circuit and is used to measure the current of amps passing through. It is used as testing equipment for a variety of electrical components and usually combined with a voltmeter, measuring the potential difference or voltage between two points. An amp meter can be built with everyday items around the home, making it a fairly reasonable do-it-yourself project.

Things You'll Need

• Fuse holder
• Fuse
• Multimeter (Volt OhMeter)
• Multimeter test leads/probes
• Model amp meter

Instructions

Do-It-Yourself Amp Meter

1. Wire in the fuse and fuse holder. The fuse acts as a shunt to read the voltage across the current.

2. Connect the multimeter. The test leads or probes of a multimeter should have small alligator clip ends so that the multimeter can fasten to both sides of the fuse. Before clipping the ends to the fuse, pull back a bit of the fuse holder insulation to make better contact.

3. Calibrate the amp meter. This is where the model amp meter comes in. Use the model amp meter to calibrate your new amp meter. The model amp is ideally more expensive than the homemade amp meter. Take readings with the model amp meter and create a table to translate the homemade meter's readings into amps.

Tips & Warnings

• It is ideal to use a fuse when making a cheap amp meter because fuses don't vary much from one to another and are reasonably priced.

References

• Isaac Exploratorium: 15 Curent Ammeter
• Marcee: AMPMeter