Measuring High Current with a Low Current Ammeter: The Art of Adding a Shunt Resistor (019d)

You have a low amperage analog ammeter in your hand and you want to be able to measure higher currents with it.

In this video you will learn how to create a home grown, higher amperage ammeter from that low amperage meter by adding a shunt resistor.

I will step you through the process from the beginning to end using my own 50 microamp meter as the guinea pig.  I will create a 250 milliamp meter out of it.

My end product agrees with my DVM within 0.32%!

Here is the link to the formula sheet:
https://drive.google.com/file/d/1BO4i...

NOTE: A standard Kelvin Connection for measuring resistance places the voltage measurment immediately at the terminals of the resistor in question. The current is usually applied outside these terminals. In this case, I had two terminals. Placing the voltage measurement connection outside the current connection used the leads extending outside of the current connection of the shunt resistor as "extensions" to the voltmeter leads with negligable voltage drop.  See my video on "Measuring Low Value Resistors" for more information/explanation.

----------------------------Time Marker Notes
00:05   Introduction
00:50   Preliminaries & What are we doing?
02:18   The Basis of how this works
03:01   Resistor Calculation - the easiest way...
03:23     Calculate the Voltage across the Meter Movement
03:56     Calculate the Current through the SHUNT resistor
04:31     Calculate the Value of the Shunt resistor
05:23     Calculate the Power Dissipation of the Shunt resistor
06:19   Finding an Off-the-Shelf resistor
07:41   Build my own Shunt resistor
10:39   Measuring my Shunt resistor's value
11:03     Setup
13:13     Making the measurements.
14:00     Calculate the value from measured values
15:10   Testing your Design
15:11     Zero your meter
15:23     Install the Shunt resistor
15:32     You could locate the Shunt remotely!
15:54     Measurement setup
16:46     Test Connections
17:24     Making the measurements
18:29     Evaluate the results
19:26   Final comments & toodle-oots
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• #shunt_resistor