Status and review

1. Sallen-Key filter

1.1. Structure

wp Sallen Key Generic Circuit
Figure 1. Generic Sallen-Key topology

Wikipedia: Sallen-Key topology

  • Zx: R or C combinations make the overall response high/low/band-pass.

1.2. Single-transistor example

sallen key 1t hpf
Figure 2. Sallen-Key high-pass filter [1]

Transistor Active High Pass Filter Circuit

  • How should this circuit change to make it a low-pass filter?

1. from https://www.electronics-notes.com/articles/analogue_circuits/transistor/active-high-pass-filter-circuit.php