How to Calculate Resistor Values in an L Pad

An L-pad is essentially a sliding rheostat used in audio setups, be it in your car or in your home audio setup. To calculate the resistance values in an L-pad, you need to test the individual resistors with a multimeter set to resistance. This will then tell you what the individual resistances are of the wires. You can then determine what the resistance value of the L-pad is by checking the setting of the the slide.

Instructions

1

Turnon the circuit with which you are working. Ensure that there is power flowing from the power source to the audio player by turning the multimeter dial tothe voltage setting. Plug the probes to the voltage holes on the face of the multimeter. Touch the red probe to the wire going into the L-pad and the black probe to the wire coming from the L-pad. If the multimeter displays a positive voltage, then you have a live current.

2

Slide the L-pad slide to the topmost setting. Turn the multimeter to the resistance setting and plug the probes into the resistance holes in the face of the multimeter. Put the red probe on one side of the resistor in the L-pad that is connected to the top setting contacts. Place the black probe on the other side of the resistor that is connected to the top settings contacts. Read the resistance value and write it down.

3

Slide the slide down to the next lower setting and place the robes on either side of the resistor connected to those contacts. Write down the resistance value. Repeat this process for all the resistors in the L-pad to obtain the resistance value of the L-pad.