08-11-2012, 03:05 PM
The op-amp appears to be powered from the outgoing supply rail - as I mentioned in my last post, the op-amp inputs don't work correctly when near to a supply rail. The op-amp needs to be powered from something that is a few volts more than the inputs.
Also, you need a resistor between the output of the op-amp and the LED.
Remember, the op-amp output will be at one rail or the other - which is correct because you are using it as a comparator, not an amplifier. Stick 1K or thereabouts in series with the LED. Then, the 1M hysteresis resistor might do something.
Also, you need a resistor between the output of the op-amp and the LED.
Remember, the op-amp output will be at one rail or the other - which is correct because you are using it as a comparator, not an amplifier. Stick 1K or thereabouts in series with the LED. Then, the 1M hysteresis resistor might do something.
