Hot answers tagged


A typical voltmeter contains an internal Ohmic resistor with known and very high resistance $R$ (called the "input resistance" or "input impedance"), and an extremely sensitive ammeter that measures the current through that resistor. When the voltmeter is connected in parallel across some circuit elements, then ideally the internal resistor has resistance ...


A lot of these problems are best done by first redrawing the circuit so that it is in a more accessible form. The correct answer is $\frac 8 3 \;\mu$F.


The component that ensures the current is zero just after the switch is closed is the inductor. Inductors do not like changes in current, since a change in current means the magnetic field linking the inductor is changing and this generates a back emf that opposes the change. If you replace the inductor with a piece of wire you would have an RC circuit and ...


Setting up the differential equation $$L \frac {dI}{dt} + RI + \frac {Q}{C} = V$$ will not necessarily answer your question, "What and how can I conclude about the current in this circuit just after switch is closed." If you look at the methods of solving the differential equation somewhere on the way to the solution initial conditions are needed, one of ...

Only top voted, non community-wiki answers of a minimum length are eligible