Is there a simple way to add a tiny offset so that the comparator switches at (say) \$ V_ > V_- offset \$? That would allow me to guarantee the comparator output when the inputs are equal. However, I can't be sure if the output will switch to ground, since the output state of the comparator is undefined when the inputs are equal. When the load is disconnected, there is no drop across the resistor, and so the comparator inputs are (very close to) equal. When current is flowing, there will be a drop across the sense resistor, one comparator input will be higher than the other and so the comparator output will go to (say) 5V. The approach I thought of was to put a small sense resistor between 5V and the load, and use a comparator to detect the voltage drop across the sense resistor. The load resistor is a photoresistor and can vary from 50k\$\Omega\$ up to 2M\$\Omega\$ and is driven by 5V to ground. ![]() ![]() ![]() I need to detect if a load resistor is taken out of circuit.
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