L-pad impedance matching calculator is designed to calculate the parameters needed to design a L-pad network between different source and load impedances.
L-Pad Impedance Calculator
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This L-pad Impedance Calculator is an interactive online tool is specifically designed to calculate the impedance match between two unequal impedances.
The L-pad Network is a simple circuit consisting of resistors, inductors, and capacitors (RLC) which can be used to match a wide range of impedances in order to maximise the power transfer between a source and connected load. The simplest impedance-matching network is the “L-pad” configuration.
As its name implies, an L-pad is a circuit topology composed of two series connected impedances which forms a simple voltage-divider network with one arm and one leg (one in parallel with the load and one in series) that resemble and upside-down capital letter “L” when drawn as a schematic circuit.
L-pad Impedance Matching Configuration
Note that the L-pad impedance network is an asymmetrical design, meaning that its impedance is different looking into each side. Thus an L-pad impedance matching network cannot be used between two equal impedances if an impedance match between the source and load is to be maintained in both directions.
L-pad Impedance Calculator
Impedance Matching Calculator
How to Use this L-pad Impedance Calculator
There are some important points to understand when using this interactive L-pad impedance matching tool. While the circuit topology can change depending on the inputs, in all topologies there is one inductor and one capacitor. However, the location of these two components can change.
There is one menu item to select if there is to be any DC current passing or not, that also affects the topology. The inputs ask for source resistance and source reactance. If you are unsure what the reactance is set it to zero for a first pass approximation.
The outputs of this L-pad impedance calculator tool will give you the correct component values as well as a graph of the impedance looking into the L-pad network directly from the source.
This allows you to double check the calculator and make sure that it selected appropriate values, by making sure the impedance correctly matches the input impedance. Also remember that the circuit input reactance will be opposite in polarity with the source reactance when matching.
Tutorial Summary
In this online calculator tutorial we have looked at impedance matching by means of an L-pad network. Transferring maximum power from a driving source to a connected load is known as impedance matching and there are a wide variety of components and circuit configurations we can be use. One of the most common impedance matching techniques is that of an L-pad impedance network.
The L-pad network is nothing more than a simple voltage-divider network with minimum loss. Finding the values for the inductance, L and capacitance, C will provide the correct impedance match in both directions. However, one point to note is that the upside-down L-pad design is asymmetrical meaning that the impedance docs not look the same from both directions.
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