The CL version shows the basic ideas but the LTspiceIV version runs much faster and it is far easiler to see the detail of the waveforms concerned.
There are some minor differences between the LTspiceIV and CL versions to do with the availability of models: namely the CL version uses the 2N7000 MOSFET which has a somewhat different SOA compared to the 2N7002 used in LTspice.
