Question

When making an ECG measurement, it is important to measure voltage variations over small time intervals. The time is limited by the \(RC\) constant of the circuit-it is not possible to measure time variations shorter than \(RC\). How would you manipulate \(R\) and \(C\) in the circuit to allow necessary measurements?

Short answer

Putting resistances in parallel and capacitors in series.

Step-by-step solution

Discharging of a capacitor

The capacitor discharges if the plates of a charged capacitor are connected by a conducting wire. Once more, there is a current because there is a movement of charge across the wires. \({\bf{q}} = {\bf{QeCR}} - {\bf{t}}\).

Explanation

For measuring smaller time periods, \(R\)and \(C\) should be made smaller. This can be done by putting resistances in parallel and capacitors in series. This will reduce the effective time period of the circuit.