08-11-2012, 01:25 PM
False alarm I'm afraid. When I got to re-building it on Vero I found it was connected up wrong and DOESN'T work.
Here's the circuit:-
The 1 Meg resistor seems to make no odds.
The LED comes on with nothing connected and goes OUT when a load is applied. Swapping the inverting and non-inverting inputs doesn't seem to make any odds and this effect is inconsistent to boot.
I think that the Voltage regulator is drawing enough current off load to produce a drop of 0.03 mV across the 1Ω resistor.
This looks like one of those cases where the cruder the solution the better: a read switch would be ideal but without a massive, and therefore mechanically unstable and high resistance coil, it won't operate at low currents.
I'm now leaving as I've got so muddled up that I really don't know what I'm doing. Besides that I want my dinner.
Cheers
Joe
Here's the circuit:-
The 1 Meg resistor seems to make no odds.
The LED comes on with nothing connected and goes OUT when a load is applied. Swapping the inverting and non-inverting inputs doesn't seem to make any odds and this effect is inconsistent to boot.
I think that the Voltage regulator is drawing enough current off load to produce a drop of 0.03 mV across the 1Ω resistor.
This looks like one of those cases where the cruder the solution the better: a read switch would be ideal but without a massive, and therefore mechanically unstable and high resistance coil, it won't operate at low currents.
I'm now leaving as I've got so muddled up that I really don't know what I'm doing. Besides that I want my dinner.
Cheers
Joe
