产品描述The HHT digital stroboscopes provides reliable and accurate speed measurements as well as stop-motion diagnostic inspection. A rotary encoder enables quick, precise frequency setting from 30 to 20,000 flashes per minute. The crystal-controlled circuitry eliminates drift and allows readings accurate to 0.1 rpm. "Divide by 2" and "Multiply by 2" buttons let the user check actual rpm. With "Phase +" and "Phase -" buttons, the user can add or subtract internal phase delays to keep the reference viewing target in eyesight. An "Adder Mode" enables visual inspection for misalignment or bent odd-numbered fan blades, propellers, etc. In the "Tach" mode, the unit uses external sensors to measure up to 250,000 rpm directly without flashing the strobe. Up to 6 preset memory values can be recalled from memory, and the unit recalls the last value measured.