Build a Simple Amperometer *(Ampmeter)




Introduction: Build a Simple Amperometer *(Ampmeter)

About: I like to invent and modify things. When i was 13 i fixed my dad's old Lancia Fulvia motor. I builded my first mod PC in 1991 using a mobo builded in a VCR box. I am first using all my inventions. I love every…

Always i was wondering how many amps are the current i use in a specific circuit.

WIKIpedia says:The ampere (symbol: A) is the SI unit of electric current.The ampere, in practice often shortened to amp, is an SI base unit, and is named after Andre-Marie Ampere, one of the main discoverers of electromagnetism.

In practical terms, the ampere is a measure of the amount of electric charge passing a point per unit time. Around 6.242 � 1018 electrons passing a given point each second constitutes one ampere.[2] (Since electrons have negative charge, they flow in the opposite direction to the conventional current.)
One ampere is defined to be the constant current which will produce an attractive force of 2�107 newton per metre of length between two straight, parallel conductors of infinite length and negligible circular cross section placed one metre apart in free space. The definition is based on Amp�re's force law] The ampere is a base unit, along with the metre, kelvin, second, mole, candela and the kilogram: it is defined without reference to the quantity of electric charge.

The SI unit of charge, the coulomb, "is the quantity of electricity carried in 1 second by a current of 1 ampere.". Conversely, a current of one ampere is one coulomb of charge going past a given point per second:

\rm 1\ A=\frac{1\ C}{1\ s}

That's for the theory....
Now its time to build our very simple count the current of any circuit.


+For this instructable i use the analog panel of an Ampmeter from range 0-15Amps which costs around 6-7 Euro (
+A small box (by Velleman too) costs 4 euro
+ 2 RCA connectors female (one red and one black)
+ 2 crocodiles or pins
+ Small cables for connections and 2 large cables (up to 20cm)
+ A Dremel tool to open the big hole in the plastic box to fit the panel,some sandpaper
+ Soldering tool, Screw driver, and Some time
Total cost 10-12 euro (8-10 USD)

Step 1: Building Step

Ok...we have all the materials we need? Lets start...Oh forgot Also we need a good cup of coffee...hehehe....So let's start...

The dimmensions of the box (iforgot to mention) are 10x4x3 and are tight enough to fit the panel meter.
So we appart the cover of the box (unscrew the 4 screws) and FIRST fit the panel meter BEFORE anything else. The panel comes with some screws and nuts but believe me this is the hardiest thing in this fit tight the panel meter in the box.
After that with a soldering tool we have to solder the appropriate connectors, cables and RCA and crocodile tips. From each RCA starts on test cable which leads to the appropriate crocodile tip (Red to RED and Black to Black) From the RCA connectors we use ONLY the central cennector. That's it very simple and quick and reliable. Now screw back the box cover and your AMPmeter is ready for use

How to Use it

An ammeter is placed in series with a circuit element to measure the electric current flow through it.

Be the First to Share


    • Potato Speed Challenge

      Potato Speed Challenge
    • Bikes Challenge

      Bikes Challenge
    • Remix Contest

      Remix Contest

    8 Discussions


    9 years ago on Introduction

    With that cup of "hehehe" those who buy a meter, and smoke it because you provided incomplete information, may not laugh. Because a panel meter has a large A, and the number 15 on the meter face doesn't mean it's capable of 15 Amps out of the box. In the event it has an internal shunt it can, but meter that look identical don't have that internal shunt and need to be used with a shunt mounted in the enclosure or elsewhere. I hope you can do better by your paying customers than you did for your non-paying customers here. Because I left out an important detail I deleted my first comment, and posted this. Sorry if you get two from me.


    11 years ago on Introduction

    So what are you telling us to do? Wire up an ammeter to make an ammeter? Try to actually make an ammeter (its possible) and then I'll say its good. Although, I must admit that you did do a very clean job...


    Reply 11 years ago on Introduction

    ofcourse the ammeter panel is already done as job but here i build an's quite different...;)

    Callum Snowden
    Callum Snowden

    Reply 9 years ago on Introduction

    I wouldn't use RCA jacks because of fear that they wouldnt handle the current because they are designed for carrying small voltages and no current at all basically because they are designed for audio and video :)


    Reply 9 years ago on Introduction

    yes...but i use this instruments for currents up to 2 Amp

    brandon borick

    he means like the kind you buy at the hard ware store fo electical work.

    My dads a elictishon or how ever you spell it