100 Amp Shunt - 50 mV Output

justmatt83

Hello -

I have been searching for about a week now trying to find a way to read amp flow. I was wondering if any one has a schematic for a amp meter or if anyone can point me to some reading material. I was thinking about using a 100 Amp Shunt - 50 mV Output but I don't know how it works so if anyone has worked with them before and can point me in a direction to get this project started I would appreciate it. Thanks

Mike Green

Current is usually measured using a small value resistor in series with the load and a voltmeter of some kind measuring the voltage across the resistor.· Ohm's law gives the current (I = E / R).

The value of the resistor used depends on the overall voltage in the circuit (you don't want to drop a large proportion of the voltage with the resistor) and the current expected (for the same reason).

What kind of current do you expect to measure?· What kind of voltage powers the circuit?· Is it AC or DC?

Often, since the voltage to be measured is usually fairly low, you will use an op-amp to amplify this to something more easily measured by a microcontroller.· Most op-amps also have a differential input (+ and -) and this can usually be connected across the shunt resistor even though the voltage at those points may be above ground.

Post Edited (Mike Green) : 6/20/2007 12:04:02 AM GMT

bennettdan

Hey I have used these shunts before and they have great details and good support if you need it this should get you started.
http://www.deltecco.com/resources.html
·I use a 100mv shunt (.1volt) feed into an op-amp with a gain of 25 that gives me a 0-2.5 volt scale.

Post Edited (bennettdan) : 6/20/2007 12:14:03 AM GMT

justmatt83

Thanks for the info. I plan on using this in my pickup truck to measure volts, amps, temp, speed, rmp, auto headlights, and other stuff when I can think of it. This is DC off course and will be anywhere from 40 amps to 100 with lights and stereo.