461891-en-US_V2.1 8/15
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Introduction
Congratulations on your purchase of Extech’s Digital Tachometer, model 461891. This meter is
shipped fully tested and calibrated and, with proper use, will provide years of reliable service.
Features
Measures from 0.5 to 19999 rpm
Min/Max Memory Recall
Cone, funnel, surface attachments included
Quartz crystal time base
Specifications
General Specifications
Circuit
Custom one-chip LSI microprocessor circuit
Time base
Quartz crystal
Display
5-digit multi function LCD display
Measurements
Rotation Speed 0.5 to 19,999 rpm
Surface Speed 0.2 to 6560 ft/min.
0.05 to 1999.9 m/min
Memory
Last and Max/Min readings
Sampling Time
1 second
Operating Temperature/RH
32 °F to 122 °F (0 °C to 50 °C) / <80% RH
Power Supply
4 x 1.5V AA batteries
Power Consumption
Approx. 10 mA
Weight
0.62 lb (280 g) including batteries
Dimensions
8.2 x 2.8 x1.5" (208 x 72 x 37 mm)
Accessories
Cone rpm adaptor, funnel rpm adaptor, surface speed
test wheel, and carrying case
Range Specifications
Range
Resolution
Accuracy
rpm
0.5 to 19,999 rpm
0.1 rpm (0.5 to 999.9 rpm)
1 rpm (over 1000 rpm)
+ (0.05%
rdg +1d)
@23+ 5oC
ft/min
0.2 to 6560 ft/min
0.1 ft/min (0.2 to 999.9 ft/min)
1 ft/min (over 1000 ft/min)
± (1% rdg + 1 digit)
m/min
0.05 to 1999.9 m/min 0.01 m/min (0.05 to 99.99 m/min)
0.1 m/min (over 100 m/min)
