Filtered Voltage Divider

This formula calculates the cutoff frequency of the RC voltage divider using the equivalent resistance of the top and bottom resistors in parallel. The solution is approximate. This approximation assumes: No load on the divider node. Ideal source. No series resistance before the divider. Capacitor ESR negligible.

\(f_c = \frac{1}{2 \times 3.14159 \times \left( \frac{R_{TOP} \times R_{BOT}}{R_{TOP} + R_{BOT}} \right) \times C_{FILT}}\)

Instructions: Select the variable you want to solve for, and fill in the others.

Solve Symbol Input Value Unit Description
\(R_{TOP}\)
\(\Omega\)
\(R_{BOT}\)
\(\Omega\)
\(C_{FILT}\)
\(F\)
\(f_{c}\)
\(Hz\)

References