Faculty Research at Morehead State University


Period and pulse duration with “strobe” lights

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Strobe lights have traditionally been discussed in The Physics Teacher in the context of stop action strobe photography. During the Halloween season most department and hardware stores sell inexpensive, compact “strobe” lights. These lights generally sell for under $10 and usually employ LED lights. Most such devices have a rotary switch to adjust the rate at which the LED bulbs flash. This rotary switch is not calibrated—i.e., it has no markings to indicate the rate, but in general the greater the rotation of the switch from the off position, the faster the rate of flashing. We show how these simple devices can be used with a light sensor to study both the frequency of flashing and the duration of the light pulse. We briefly discuss if these devices are truly strobe lights.