E.7.3 RC and RL circuits -- Exponential Decay

A relaxation oscillator circuit as in E.2.2 demonstrates the RC time constant by a flashing neon bulb.

With a square wave input the voltage across the capacitor shows the exponential decay on an oscilloscope.

You could roughly measure the time constant t c= RC from the oscilloscope trace. With a similar circuit for RL you could estimate the time constant tL = L/R. These circuits are analyzed and their oscilloscope traces depicted in Halliday and Resnick, Part 2; for RC, Section 32-8, pp 705 -709; and for RL in Section 36-3, pp 798 - 801. As discussed in E.7.5, the same circuits will integrate and differentiate waveforms.