5.4.3 Types offilters RC-network is connected to the input terminal of an op-amp The filter's cut-off frequency is then R and its gain K=1+ 2ITRC Connecting a high-pass network to the feedback loop at the amplifier yields a low-pass filter. As shown in Fig. 5.43(b), the filter has a cut-off frequency c2 2,c and its gain x Re f∫ R5.4.3 Types of filters RC-network is connected to the input terminal of an op-amp. The filter’s cut-off frequency is then : RC f c 2 1 2 = and its gain 1 1 R R K F = + Connecting a high-pass network to the feedback￾loop at the amplifier yields a low-pass filter. As shown in Fig. 5.43 (b), the filter has a cut-off frequency : R C f F c 2 1 2 = and its gain R1 R K F =