# How can I measure total current used

I have a circuit that includes an arduino and an electromagnet thats periodically turned on. I can easily measure the current consumed when its turned on and when its off by wiring in my multimeter in series and observing the drain. However I want to know how I can measure the total current consumed (for example overnight). The frequency in which the electromagnet will be turned on will be somewhat random.

This is the multimeter I have https://www.amazon.co.uk/gp/product/B01N3RVVJ4/ref=od_aui_detailpages00?ie=UTF8&psc=1

I've seen some multimeters that have the capability to measure total current passed in, by the looks of it mine doesn't have that. I did consider buying one of those USB multimeters which can do this and splicing the wires to connect it in series with my circuit but I figured surely there's a better way to measure this?

• There exists logging multimeter which can measure the average current over long periods of time. They are pricey though. Commented Apr 19, 2017 at 14:15
• "Current" is a rate of flow of charge, or combined with voltage gives you a rate of flow of energy so "Total current" is a rather meaningless concept. If the electromagnet always takes the same current, you could work out average current and/or total power by getting your arduino to record the amount of time it turns the electromagnet on for. Commented Apr 19, 2017 at 14:19
• You cannot have what you call "Total current" since current is rate at which electrons are going through a medium. What you should look into is the total power consumed. Commented Apr 19, 2017 at 14:33
• "Milliamps per hour" IS meaningless. It's like saying "revolutions per minute per hour" Commented Apr 19, 2017 at 15:25
• @Finbarr or in the case of the question here, "charge". If you're going to be picky, at least be right. Commented Apr 19, 2017 at 15:53