Sensor Selection Guide Calculator

Sensor type and specs from measurement requirements.

Resistance (Ω)

Capacitance (µF)

Supply Voltage (V)

Target Charge (%)

Tab to move between fields

Time Constant τ (ms)

1,000

Time to Target (ms)

999.67

Time to 63.2% (ms)1,000

Time to 99% (ms)5,000

LP Cutoff Frequency (Hz)0.16

Voltage at 1τ (V)3.16

Energy Stored (µJ)1,250

Impedance at Cutoff (Ω)14,142.14

Tau Us1,000,000

Time To95pct3,000%

How to Use This Calculator

Enter the resistance (Ω) and capacitance (µF) values for your RC timing circuit.
Set your supply voltage and the target charge percentage (e.g., 63% for one time constant).
Review the time constant τ (ms), time to reach your target percentage, and low-pass cutoff frequency.
Use these values to select the correct capacitor or resistor to achieve your desired timing.

How the result changes with Resistance (Ω)

Resistance (Ω): Resistance in ohms. Common values: 1k, 10k, 100k.
Capacitance (µF): Capacitance in microfarads. Common: 0.1µF (decoupling), 100µF (filtering), 1000µF (power supply).
Supply Voltage (V): Charging voltage applied to the RC circuit.
Target Charge (%): Desired charge percentage to calculate time for (63.2% = 1 tau).

Time Constant τ (ms): RC time constant = R × C. Time to reach 63.2% of final voltage.
Time to Target (ms): Time to reach your specified charge percentage.
Time to 63.2% (ms): Time to charge to 63.2% (1τ).
Time to 99% (ms): Time to charge to ~99% (5τ). Considered fully charged.
LP Cutoff Frequency (Hz): Low-pass filter -3dB cutoff: f = 1/(2πRC).
Voltage at 1τ (V): Capacitor voltage after one time constant.
Energy Stored (µJ): Energy stored when fully charged: E = ½CV².
Impedance at Cutoff (Ω): Circuit impedance at the cutoff frequency.

Identify Input Parameters
4 parameters
Resistance (Ω) = 10000, Capacitance (µF) = 100, Supply Voltage (V) = 5, Target Charge (%) = 63.2 = 4 input(s) provided
Calculate Time Constant τ
Time Constant τ = tauSeconds * 1000
1000 = 1000
Calculate Time to Target
Time to Target = timeToTarget * 1000
999.672 = 999.672
Calculate Time to 63.2%
Time to 63.2% = tauSeconds * 1000
1000 = 1000
Calculate Time to 99%
Time to 99% = tauSeconds * 5 * 1000
5000 = 5000