Extech 461895 Combination Contact/Photo Tachometer


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Extech 461895 Combination Contact/Photo Tachometer


  • 461895 Tachometer Combination Contact Photo
  • Unique display where characters reverse direction depending on measurement mode you are in
  • Large 0.4” (5 digit) LCD display
  • Microprocessor based with quartz crystal oscillator to maintain high accuracy
  • Tachometer memory stores last, max and min readings
  • Provides wide RPM (photo and contact) and
  • Linear Surface Speed (contact) measurements
  • Accurate to 0.05% with max resolution of 0.1rpm in either photo or contact mode
  • Complete with tips and wheel for rpm or linear surface speed, four 1.5V AA batteries, reflective tape and carrying case
Extech 461895 Tachometer Combination Contact Photo.
Combination Contact/Photo Tachometer
Combines both contact (0. 5 to 19,999 rpm) and non-contact (5 to 99,999 rpm) models for use in virtually all applications.Uses visible light for non-contact measurements up to 6 inches (150mm) from target.

Make non-contact RPM measurements of rotating objects by pointing the integral laser at the reflective tape placed on the object to be measured. Characters on the display reverse direction depending on contact or photo mode. The memory button holds last reading and recalls min/max readings display.

What is a Tachometer?
A tachometer is a device that measures the angular speed of a rotating shaft in terms of revolutions per minute (RPM). Also, a tachometer can measure linear speed in terms of feet per minute (feet/minute) or meters per minute.

How do Contact Tachometers Operate?
The sensor tip is placed in direct contact with the rotating object. After 2 seconds an accurate reading is displayed. Linear surface speed can also be measured by placing the edge of the wheel on the moving object.

How do Photo (Non-contact) Tachometers Operate?
First, a small piece of reflective tape (approximately 1/4-inch) is mounted on the object to be measured. Second, the light beam or laser is pointed at the revolving tape. The reflection from the tape provides a reading to be displayed and updated once per second. For the most accurate measurements, the distance between the tachometer and the reflective tape should be within 6 inches for a light beam and up to 6.5 feet for a laser. Fluorescent or bright ambient lights may interfere with the measurement.

Which Extech Tachometer Model Is the One for You?
A non-contact (photo) tachometer was designed for applications where it is not feasible to have the tachometer come in contact with the rotating device. This is the case in high-speed applications and/or where the object to be measured is not easily reached. A contact tachometer is also available for applications where direct contact of the tachometer with the object is preferred. You can also select a combination (contact/non-contact) tachometer for the maximum in flexibility.

461937 Reflective Tape for Photo Tachometers
For use with any brand Photo Tachometer. Place a piece of reflective tape on the object to be measured and point the tachometer's integral light beam at it. Ten reflective tape strips. Each strip measures 23 x 0.25 inches (584 x 6 mm).

461990 Replacement Wheels for Contact Tachometer
Two sets of cone tip, flat tip, and spare wheel.


General Specifications
Circuit Custom one-chip LSI microprocessor circuit.
Time base Quartz crystal
Display 5 digit, 10 mm (0.4") LCD display with function annunciation
Measurement Photo Tachometer - 5 to 99,999 rpm, Contact Tachometer - 0.5 to 19,999 rpm, Surface Speed - 0.2 to 6,560 ft/min, Surface Speed - 0.05 to 1,999 m/min
Memory Last value, last max. reading, last min. reading
Sampling Time Photo Tachometer - 1 sec. (over 60 rpm), Contact Tachometer - 1 sec. (over 6 rpm)
Detecting Distance Photo Tachometer 50 to 150 mm (2 to 6 inches) depending on ambient light
Operating Temperature 32 °F to 122 °F (0 °C to 50 °C)
Power Supply 4x 1.5 V AA (UM 3) batteries
Weight 0.66 lbs. / 300g (including battery)
Size 8.5 x 2.6 x1.5” (215 x 65 x 38mm)
Accessories Reflective tape (23"), cone and funnel rpm adaptor, surface speed test wheel, and carrying case
Electrical Specifications
Photo Tachometer 5 to 99,999 rpm
Contact Tachometer 0.05 to 19,999 rpm
Surface Speed 0.2 to 6560 ft/min
Surface Speed 0.05 to 1999.9 m/min
Product Images (click to enlarge)
  • Extech 461895 Combination Contact/Photo Tachometer