L lang="en">RC Time Constant
Measurement that the Time constant in one RC Circuit
In this rap experiment we will measure the time continuous τ of an RC circuit via three various methods. In number 1 we"ve sketched a collection RC circuit.
Figure 1 - chart of an RC CircuitWhen the move is in position 1, the voltage resource supplies a present to the resistor and also the capacitor. Charge is deposit on the plates of the capacitor. At very first there is very little charge on the plates, however, together time walk on the charge on the plates builds up and the increased voltage throughout the capacitor will minimize the flow of existing through the circuit. We deserve to see this in the following loop equation:Vo + Vr + Vc = 0orVo - iR - q/C = 0As q gets larger, ns must obtain smaller to compensate. As time goes on, the currentwill eventually technique zero. When the move is moved to place 2, the battery is eliminated fromthe circuit, and the charge that has accumulated in the capacitor flows through the resistor. In this situation the equation is:iR + q/C = 0ordq/dt R + q/C = 0This an initial order differential equation has actually a systems in the type of an exponential:q(t) = qo e(- t / τ)Where τ = RC. This decaying role is plotted in figure 2:
Figure 2 - Exponential DecayGiven the worths of R and also C in most circuits, it is really hard to "watch" the decay. In this rap we will certainly cheat a little bit, we will affix our RC circuit not to a voltage supply v a switch, however to a role generator that is outputting a square wave. This will act as an "on" and also "off" voltage supply hundreds or countless times per second. We can then observe the voltage across the circuit on one oscilloscope, and also measure τ from there.

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