From Dave G3YMC Andy will find an updated version of the huff and puff, using a CD4013 counter, in Technical Topics in the April 1978 issue. This is a reprint of the version which appeared in Ham Rad
I'm looking for the reference to the Huff-Puff stabilisation scheme, and in particular the improved Mark 2 modified version that, seem to recall, employed a counter rather than a simple flip-flop. I