E8T Miniature Optical Kit Encoder

E8T Features

  • Push-on hub - spring loaded collet design
  • Minimum shaft length of .295 in.
  • Fits shaft diameters of .118 in. to .375 in.
  • 180 to 720 cycles per revolution (CPR)
  • 720 to 2,880 pulses per revolution (PPR)
  • Single +5V supply

See more info below

Configure the E8T

E8T Product Description

Restriction of Hazardous Substances

The E8T transmissive optical encoder is designed to provide digital quadrature encoder feedback for high volume, compact space applications. The E8T is designed to be a drop in replacement for the E7P/E8P that offers higher maximum speed and increased output drive. The E8T utilizes an innovative, push-on codewheel which accepts shaft diameters of .118" to .375".

The E8T is designed to be a one-time installation miniature encoder, the base provides mounting holes for two #4-40, length 0.188" or two M2.5, length 5mm screws on a 0.75" bolt circle diameter. A 1.28" diameter bolt circle mount is also available, only with #4-40, length 0.188" screws. The encoder cover is easily snapped onto the base and is marked with the connector pin-out.

The single-ended output version is connected using a 4-conductor, high retention, polarized, 1.25mm pitch connector. The differential output version uses a similiar 6-pin connector. Mating cables and connectors (see the Cables / Connectors web page) are not included, and are available separately.    

Please Note: Due to the E8T's design, it is recommended for use as a one-time installation. 

Product Specifications

View here or download the specifications


Operating Temperature -20 to 100 C
Electrostatic Discharge, IEC 61000-4-2
Single-ended (-S option)
Differential (-D option)

± 12
± 7

Shock, 6 millisecond, half-sine 75 G
Vibration (20Hz to 2kHz, sinusoidal) 20 G


Parameter Value Units
Max. Shaft Axial Play ± .010 in.
Max. Shaft Runout 0.002 T.I.R. in.
Max. Acceleration 250000 rad/sec²

Maximum RPM (1)
e.x. CPR = 500, max. rpm = 12000
e.x. CPR = 200, max. rpm = 30000

minimum value of
((6 x10^6) / CPR)
and (60000)
Codewheel Moment of Inertia 1.789 x 10^-6 oz-in-s²
Mounting Screw Size
Default (D-option), 1.28" base (G-option)
Metric (M-option)
#4-40 x 3/16
M2.5 x 5
Screw Bolt Circle Diameter
Default (D-option), Metric (M-option)
1.28" base (G-option)

0.75 ±0.005
1.28 ±0.005

Minimum Shaft Length (2) 0.295 in.
Maximum Shaft Length (2) 0.400 (D option) /
no limit (H option) 
Mounting Screw Torque 2-3 in-lbs
Technical Bulletin TB1001 - Shaft and Bore Tolerances Download

(1) 60000 RPM is the maximum rpm due to mechanical considerations. The maximum RPM due to the module's 100kHz maximum output frequency is (6000000/CPR).

(2) Including axial play.

Single-ended Electrical

Supply Voltage 4.5 5.0 5.5 V  
Supply Current   25 30 mA no load
Low-level Output     0.4 V IOL = 8 mA
  0.035   V no load
High-level Output 2.4     V IOH = -8 mA
  4.0   V no load
Output Rise Time   100   ns no load
Output Fall Time   50   ns no load

Differential Electrical

Supply Voltage 4.5 5.0 5.5 V  
Supply Current   27 32 mA no load
Differential Output Voltage High 4.75 5.0   V Min. @ 25mA load, Typ. @ no load
Differential  Output Voltage Low   0.25 0.60 V Typ. @ no load, Max. @ 4.5mA load
Differential Output Voltage 3.0 3.8   V RL = 100 ohm
Differential Output Rise/Fall Time     20 ns

Phase Relationship


Symmetry, S 105 180 255 electrical degrees
Quadrature Delay, Q 30 90 150 electrical degrees

(1) A leads B for clockwise shaft rotation, B leads A for counter clockwise shaft rotation viewed from the cover side of the encoder.

(2) Typical values represent the encoder performance at typical mounting alignment, whereas the maximum values represent the encoder performance across the range of recommended mounting tolerance.


4-pin Single-ended (1)6-pin Differential (2)
1 +5VDC power 1 Ground
2 A channel 2 A channel
3 Ground 3 A- channel
4 B channel 4 +5VDC power
    5 B channel
    6 B- channel

(1) 4-pin single-ended mating connector is CON-MIC4
(2) 6-pin differential mating connector is CON-MIC6


H-option (Hole In Cover)

The H-option adds a 0.425" diameter hole in the cover for the shaft to pass through.

M-option (Metric Mounting Screws with Default base)

Provides metric M2.5, length 5mm screws. When M-option is NOT specified the default is #4-40, length 0.188" screws. The mounting bolt circle diameter is 0.75" 

G-option (1.28" diameter bolt circle mount)

Provides 1.28" diameter bolt circle mount in addition to 0.75" diameter bolt circle mount. Screws are #4-40, length 0.188"


1. Centering Tool*

Part #: CTOOL - (Shaft Diameter)
Description: This reusable tool is used to accurately center the E8T base on the shaft.

2. Spacer Tool*

Part #: SPACER-E8T
Description: This reusable tool is used to properly gap the codewheel from the encoder sensor.

*Both the CTOOL and SPACER-E8T tools are included with all packaging options.

3. Screws

Part #: SCREW-440-188-PH
Description: Pan Head, Philips #4-40 UNC x 3/16"
Use: Base Mounting
Quantity Required: 2
Screws are included

Part #: SCREW-M25-5MM-PH
Description: Pan Head, Phillips M2.5 x 0.45 x 5mm
Use: Base Mounting
Quantity Required: 2
Screws are included

Product Change Notifications

Updated PCB on the US Digital E8T - PCN 6514 5/16/2018 This notice is to inform our customers of a PCB design change that is being implemented for the entire E8T product line. As part of our continuous improvement objective, the new PCB will improve overall product performance and enhance robustness of this product line. The new PCB has two mounting holes that mate with the base plate instead of one hole and one slot. This change has no impact on form, fit or function for the E8T. Download
E4T, S4T and E8T Laser Markings - PCN 6227 8/8/2017 This notification is to inform our customers of a change to product markings for the E4T, E8T, and S4T series of encoders. The new marking will be utilized across all three product lines. We are making this change to improve readability for our customers and to provide consistency across the product lines.

Additional Information

Downloads Available



3D Model Downloads

Please configure your product first to download a 3D model.
(Note: The formats below will become links if there are 3D models available.)

    • SolidWorks format
    • IGES format
    • Parasolid format
    • STEP format

    Product Configurator

    For pricing, this product requires configuration.

    Begin by completing either Option 1 or 2 below. Questions? Contact our support team.

    Option 1: Configure the Product

    Use the configuration tool to provide information regarding your product needs. Not sure what to do or need additional assistance? Our support team is here to help.

    We recommend enabling Javascript when using the product configurator.

    1. CPR

    2. Bore

    3. Output

    4. Cover

    5. Base

    6. Packaging

    Option 2: Enter the Product Part Number Directly

    If you know your product part number, enter it in the following field. The part number format looks something like this: E5-5000-394-IE-S-D-D-3...

    E8T Pricing

    Quantity Unit Price
    1 $35.50
    5 $31.58
    10 $30.33
    50 $29.42
    100 $28.92
    Over 100 Call for Quote
    Quantity Unit Price Subtotal
    $35.50 $35.50

    For purchasing or volume discounts, please configure the part above, then use the completed part number and contact us!


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