LM2903Dual voltage comparator

LM2903 contains two independent voltage comparators with open-collector outputs. Each channel compares its positive input with its negative input and either sinks output current or releases the collector. An external pull-up resistor supplies the HIGH state. This page selects classic TI LM2903P in PDIP-8 and LM2903DR in SOIC-8, rated for −40 to +125°C. It uses the non-B electrical table; LM2903B and V/AV variants have different limits. All eight physical pins keep the same function when switching between these two packages. The 5 V example compares a 1.50 V signal with a nominal 2.00 V resistor-divider reference. A 10 kΩ output pull-up and 100 nF supply bypass complete the first channel; the unused channel is tied to defined inputs. Offset, input current, resistor tolerance and noise affect the real threshold. The interactive explorer marks uncertainty near equality rather than pretending the decision is exact.