Low-Pass Filter (RC)

Here is an example of an RC low-pass filter. This circuit passes low-frequency signals and blocks high-frequency signals. When a DC voltage is applied, the capacitor starts to charge through the resistor. The voltage across the capacitor increases over time, approaching the input voltage. This demonstrates the "integrating" behavior of a low-pass filter.

export default () => (
    <board width={16} height={16} schMaxTraceDistance={5}>
      <voltagesource
        name="V1"
        voltage="5V"
        schX={-4}
        schY={1}
        schRotation={270}
      />
      <resistor
        name="R1"
        resistance="187ohm"
        footprint="0402"
        schX={-1}
        schY={0}
      />
      <capacitor
        name="C1"
        capacitance="10uF"
        footprint="0402"
        schX={2}
        schY={1}
        schRotation={270}
      />

      <trace from={".V1 > .pin1"} to={".R1 > .pin1"} />
      <trace from={".R1 > .pin2"} to={".C1 > .pin1"} />
      <trace from={".C1 > .pin2"} to={"net.GND"} />
      <trace from={".V1 > .pin2"} to={"net.GND"} />

      <voltageprobe connectsTo={".V1 > .pin1"} />
      <voltageprobe connectsTo={".C1 > .pin1"} />

      <analogsimulation duration="15ms" timePerStep="0.1ms" spiceEngine="ngspice" />
    </board>
)

The simulation results show the voltage at the input and the output voltage across the capacitor. The output voltage charges exponentially towards the 5V input, characteristic of a low-pass filter's response to a step input.