LED testing sensors immune from spikes
Optomistic Products’ LightProbes are small programmable sensors used for testing of LEDs from a simple check for a specific color, or identifying the correct color and intensity from a spectrum of colors, including white LEDs, offering the choice of digital or analog output.

Universal LightProbe sensors operate at any voltage from +5 V to +40 V sand can withstand reverse polarity up to -18 V without permanent damage. This provides immunity from accidental power supply wiring mistakes, and from reverse polarity up to -18 V 'spikes' due to dc power line inductive switching transients.
The sensors are also immune to inadvertent reverse polarity 'shorts' testers, while permitting their operation from different dc supply voltages commonly encountered in industry.