platform
Version Multisim14.1
reference book "MULTISIM14 Electronic System Simulation and Design 2nd Edition"
10.3.5 Simulation experiment and analysis of active filter circuit
A typical filter circuit is an RC or RL frequency selection circuit composed of resistors and capacitors (or inductors ) connected in series and parallel, and can be divided into low-pass, high-pass and band-pass types according to the selected frequency. This passive filter without active components such as transistors does not require an additional power supply, and is suitable for high-frequency and high-power applications, but it has problems such as large size, low efficiency, and poor . Therefore, in low-power applications , an amplifier can be added on the basis of an RC or RL filter to form an "active filter" circuit, so that it can not only filter but also amplify. Compared with passive filters, active filters have the advantages of small size, high efficiency, good frequency characteristics, and strong load capacity , and have been widely used.
schematic diagram
Simulation results
B W 0.7 = 15.9 BW_{0.7}=15.9 BW0.7=15.9
theoretical calculation
The passband gain of the circuit
A u = 1 + R 4 R 2 = 9 Au=1+\frac{R4}{R2}=9 Au=1+R2 _R 4=9
Cut-off frequency
f 0 = 1 2 π R C ≈ 15.9 H z f_0=\frac1{2\pi RC}\approx15.9Hz f0=2πRC1≈1 5 . 9 Hz is
consistent with the experimental results