A timing light is a stroboscope used to dynamically set the ignition timing of an Otto cycle or similar internal combustion engine equipped with a distributor. Modern electronically controlled passenger vehicle engines require use of a scan tool to display ignition timing. Simple timing lights may just contain a neon lamp operated by the energy provided by the ignition circuit. Timing lights using xenon strobe lamps electronically triggered by the spark provide brighter light, allowing use of the timing lamp under normal shop lighting or daylight conditions.