RL Low-Pass Filter Excel Spreadsheet

MathML formula | Formula Image | Straight text formula |
---|---|---|

${f}_{c}=\frac{R}{2\pi L}$ | f_{c} = R / 2πL |

Where

f_{c} = cut off frequency, Hertz

= that frequency at which output power has fallen by half

= that frequency at which output voltage has fallen by 1/(2^0.5) = 0.707

R = resistance in Ohms

L = inductance in Henrys

The cut off frequency is defined as that frequency at which the output power has fallen by 50%, ie 1/(2^0.5) = 0.707 of the voltage.

I intend to build the circuit below to test my understanding of RL low-pass filters. The 1 Ohm resistor makes little difference to the operation of the circuit, but can be used as a convenient way to measure current (a high input impedance voltmeter connected across the 1 ohm resistor will give a reading in volts that corresponds 1:1 with the current in amps).