Worked formula example
RC Time Constant Examples
A 10 kOhm resistor and 100 uF capacitor have a 1 second time constant. The example keeps the problem, given values, formula, substitution, and copyable result sentence together so the calculator page can be opened only when values or units change.
Worked examples
| Step | Value |
|---|---|
| Problem | Find the time constant for a resistor and capacitor. |
| Given values | R = 10 kOhm, C = 100 uF |
| Formula | tau = R x C |
| Calculation | tau = 10,000 x 0.0001 = 1 s |
| Copyable result sentence | A 10 kOhm resistor and 100 uF capacitor have a 1 second time constant. |
| Step | Value |
|---|---|
| Problem | Estimate a common settling-time rule of thumb. |
| Given values | R = 10 kOhm, C = 100 uF |
| Formula | 5tau = 5 x R x C |
| Calculation | 5tau = 5 x 10,000 x 0.0001 = 5 s |
| Copyable result sentence | A 1 second RC time constant reaches about five tau in 5 seconds. |
| Step | Value |
|---|---|
| Problem | Find the RC cutoff frequency from the same time constant. |
| Given values | R = 10 kOhm, C = 100 nF |
| Formula | fc = 1 / (2 x pi x R x C) |
| Calculation | fc = 1 / (2 x pi x 10,000 x 0.0000001) = 159.15 Hz |
| Copyable result sentence | A 10 kOhm and 100 nF RC pair has a cutoff near 159.15 Hz. |
Copyable result sentence
A 10 kOhm resistor and 100 uF capacitor have a 1 second time constant.
Common mistakes
- Dropping units before the rc time constant examples substitution.
- Rounding the rc time constant examples calculation before the final step.
- Using a formula variant that does not match the known values for rc time constant examples.