Time constant of DECAY is the time it takes until the voltage is 37% of the initial value (in this case delta 3.48 V) and Time constant of RISE is the time it takes until the voltage reaches 63% of final value (in this case delta 3.48 V)? Have I got that part right? :)
+Eric Öhman Yes and no. The context is different. You are thinking of a situation in which the topologies are different for the charging and discharging circuit. Not the case in this simple RC lab experiment. The time constant is the negative of the inverse of the eigenvalue of the differential equation that describes the circuit. The circuit in this experiment has only one such ODE, either charging or discharging, so it has only one time constant. Your comment describes a situation like the one in the astable oscillator with the 555 timer. Good comment though. Do not give up!
First, Thanks for this explanation. For the 50% duty cycle input signal pulse, if the value of 5 tau (5 RC) is less than half of the (1/freq.) then the capacitor can be fully charged before the polarity of the puls changes. otherwise, the voltage amplitude of the charged capacitor can't reach its maximum value.
Thank you. C = 100 nF, R = 1 kohm. In the experiment, students measure the actual capacitance with an RLC meter, and the resistance with an ohmmeter, to compare the time constant with the one observed on the oscilloscope.
For an inductor, the solution is very similar with the caveat that one has to measure the resistance of the inductor with an ohmmeter in a separate DC test, and use the time constant formula tau = L/R, where R is the sum of the external resistance plus the resistance of the inductor. This is an approximate procedure since we are using the DC resistance of the inductor instead of the slightly greater resistance in AC.
This is the lab practical video on you tube where students can easily watch to learn how to measure the time constant in a circuit. Thank you.
Time constant of DECAY is the time it takes until the voltage is 37% of the initial value (in this case delta 3.48 V)
and
Time constant of RISE is the time it takes until the voltage reaches 63% of final value (in this case delta 3.48 V)?
Have I got that part right? :)
+Eric Öhman Yes and no. The context is different. You are thinking of a situation in which the topologies are different for the charging and discharging circuit. Not the case in this simple RC lab experiment. The time constant is the negative of the inverse of the eigenvalue of the differential equation that describes the circuit. The circuit in this experiment has only one
such ODE, either charging or discharging, so it has only one time constant. Your comment describes a situation like the one in the astable oscillator with the 555 timer. Good comment though. Do not give up!
The video is 7 years old but still helpful
Now 10 years old but still helpful
Gratidão imensa por esse vídeo tão bem explicado! 👏
I didn't get the same waveform, why ? the capacitor showing a as tringle ?
First, Thanks for this explanation.
For the 50% duty cycle input signal pulse, if the value of 5 tau (5 RC) is less than half of the (1/freq.) then the capacitor can be fully charged before the polarity of the puls changes. otherwise, the voltage amplitude of the charged capacitor can't reach its maximum value.
Great Video. Did you make a video for the theoretical part? If not do you the value of the capacitor?
Thank you. C = 100 nF, R = 1 kohm. In the experiment, students measure the actual capacitance with an RLC meter, and the resistance with an ohmmeter, to compare the time constant with the one observed on the oscilloscope.
Excellent!
YES sah good vibes!!
Superb Video
That was very helpful !!!! Thanks ;)
Video may be 3 years old but Dam did it help. Thanks
:^)
What would be the steps if it was an inductor ?
For an inductor, the solution is very similar with the caveat that one has to measure the resistance of the inductor with an ohmmeter in a separate DC test, and use the time constant formula tau = L/R, where R is the sum of the external resistance plus the resistance of the inductor. This is an approximate procedure since we are using the DC resistance of the inductor instead of the slightly greater resistance in AC.
Thank you very much
You are welcome
supeb video
Thank You!
good speed