Cursed circuits: a capacitance multiplier

Article excerpt

The lca,tuf’s thing blog takes a look at a capacitance multiplier circuit. It’s the kind of a circuit that usually doesn’t make sense at first glance because we can’t pattern-match it to anything we know: Section A is just an op-amp configured as a voltage follower. No matter what else is going in the circuit, it takes some voltage from section B and then mirrors that signal on its output leg. Section B is a capacitor that’s charging through a resistor; the voltage across the capacitor’s terminals (Vcap) will change over time. See the full review in the post here.