What is an Ammeter Shunt?
The rate of flowing current is an essential concept in electronics. Too little current won’t start up your toaster, while too much of it can set your hardware ablaze. If you’re planning on doing some DIY electrical projects, it’s essential to know the amount of current is being drawn. The humble dc ammeter shunt is a nifty tool that provides a way to do just that.
The dc ammeter shunt is a nifty device that provides a very low-resistance connection between two points in an electrical circuit. This low resistance flow path connects in parallel with the ammeter. In layman’s terms, the shunt is a built-in instrument, while other shunt types are externally connected to the circuit.
Before we discuss the mechanics of a DC ammeter, we first need to understand the process of electrical current and Ohm’s Law, which defines the relationship between current, voltage, and resistance. Ohm’s Law is the underlying principle behind the current ammeter shunt.
Imagine this: Electrical current flows through a resistor, and the voltage drop across the resistor is measured. If we know the resistance, we can calculate the current using the equation I=V/R.
Why the Ammeter and Shunts have a Parallel Connection?
The ammeter is made to measure the low electrical current and cannot measure heavy current on its own. A shunt must be connected in parallel to the ammeter for it to measure heavy electrical current.
With a parallel connection, the shunt and ammeter’s voltage drop across the meter, and the shunt’s electrical current remains the same; this means that the shunt does not affect the movement of the pointer.
How to Calculate Shunt Resistance
It’s easy to calculate the value of the shunt’s resistance as long as you have basic knowledge of algebra.
Let’s say that the circuit used to measure the current is represented with I. This circuit has an ammeter and shunt, which are connected parallel to each other. The ammeter is built to measure small or low current; we’ll represent this with the value Im. Please take note, Current I passes through the meter at a high magnitude and can burn the meter.
To measure the current I, we need a shunt in the circuit. The expression to calculate the value of resistance is:
The shunt current is calculated using this formula.
Therefore, the mathematical equation of shunt electrical resistance is given as,
Multiplying power of the shunt is the ratio of the total current to the other current that requires the movement of the ammeter coil.
The multiplying power can be found using this equation.
Therefore, the resistance of the shunt becomes:
The Construction of a Shunt
The shunt is built to maintain the temperature of the material even with substantial electrical current flows through the circuit. The shunt and its temperature coefficient display the relationship between the differences in the physical properties of the device concerning temperature changes. Its current resistance always remains constant with time.
This article was originally written by Catherine Tabuena. To find out more about her, visit www.catherinetabuena.com
