Electronics Handbook/Devices/Filter/Band-pass

Band-pass Filter
A band-pass filter can be constructed from connecting a low-pass filter with a high-pass filter.

Network LR - CR Band-pass Filter
By connecting one low-pass filter LR with one high-pass filter CR a band-pass filter can be formed that can pass the frequency band from $$\omega_1$$ to $$\omega_2$$

Band Pass Range
 * $$\omega_1 - \omega_2 $$
 * $$\frac{R}{L} - \frac{1}{RC}$$

Provide that
 * $$\frac{1}{RC} > \frac{R}{L}$$
 * $$R <\sqrt{\frac{L}{C}}$$

Net work RC - RLBand-pass Filter
By connecting one low pass filter RC with one high pass filter RL a band-pass filter can be formed that can pass the frequency band from $$\omega_1$$ to $$\omega_2$$


 * $$\omega_1 - \omega_2$$
 * $$\frac{1}{RC} - \frac{R}{L} $$

Provided that
 * $$ \frac{R}{L} > \frac{1}{RC} $$
 * $$R >\sqrt{\frac{L}{C}}$$