On Dec 20, 5:11*pm, Lemon Tree wrote:
I have posted a Negative Dynamic Resistance circuit collection along
with some other things hehttp://code.google.com/p/lemontree/downloads/list
I am no Alan Yates however maybe you will find some things of
interest.
Sean O'Connor

FWIW, one well-known negative dynamic resistance element is (the input
side of) a switching power supply. If the supply maintains a nearly
constant efficiency with changing input voltage, and the output
supplies a constant-power load, then the input power is nearly
constant with changing input voltage: the current drops as the
voltage rises. Beware a few million personal computers on a power
grid: avoid letting them excite a resonance in the grid...

(Slightly off-topic: a Google search reveals that the power community
is indeed interested in grid resonances. See "Schumann Resonance,"
for example.)

Cheers,
Tom