I'm clearly never going to be any good at analog stuff! ;-) Even with what looks (on the surface) to be a wonderfully clear explanation of how the circuit works, I still can't really grok how it operates! I mean, I can tell from the polarity on the cap that the collector of Q2 must be at a higher voltage than the base of Q1, but I am utterly failing to understand how the cap discharges through Q2. And as the cap charges (i.e. the voltage across it increases), how does the voltage on the base of Q1 increase - surely it must be decreasing (since it's tied to the negative side of the cap, which is experiencing a voltage increase across itself)? Like I said, I apparently don't have the gene for analog... :-) Noel