09-11-2012, 11:02 AM
Certainly worth looking into, Al.
I've had a re-wire and now have it configured thus:-
The LED is still permanently lit, though I THINK I know why: off load there's a drop of 3.1mV across Rs, which I assume to down to the current flowing though the 390Ω resistor and 4.7kΩ pot. This raises to 26mV on load at 25mA.
The principal seems sound; it just needs tinkering with to lower the sensitivity a bit.
- Joe
I've had a re-wire and now have it configured thus:-
The LED is still permanently lit, though I THINK I know why: off load there's a drop of 3.1mV across Rs, which I assume to down to the current flowing though the 390Ω resistor and 4.7kΩ pot. This raises to 26mV on load at 25mA.
The principal seems sound; it just needs tinkering with to lower the sensitivity a bit.
- Joe
