i am working on circuit to measure a negative voltage with a adc which will read only positive voltage(PIC MCU).i have a problem the positive of negative supply and negative of positive supply, both are grounded so clamping circuit will not work (in my observation).can anybody suggest any remedy for this problem .i want to convert -5v to +5v volt in this condition.thanks in advance
Use an inverting amplifier with a gain of -1 , see e.g. **broken link removed**. If you have to use your +/-5V supplies, you need an input and output rail-to-rail amplifier like the opAmp shown in the link, or from any other analog semi producer, see e.g. this application note: View attachment AN741.pdf .