Bob Engelhardt wrote:
Winston wrote:
Bob Engelhardt wrote:
Doncha' need a current limiter on the LED?

Nup. It's a 'shunt regulator'.
http://en.wikipedia.org/wiki/Linear_...ener_regulator

The wiki ckt has a current-limiting resistor in series with the voltage
source. Not so the posted ckt.

It *is* in the posted circuit.
Sort of.

As James mentions, the internal resistance of the PV
cell is the current-limiting resistor.

--Winston --The BSA B50T POS used a single power
zener across the battery as it's only
voltage regulator.