E4P OEM Miniature Optical Kit Encoder

E4P Features

  • Miniature size
  • Push-on hub - spring loaded collet design
  • Minimum shaft length of .375 in.
  • Fits shaft diameters of .079 in. to .250 in.
  • Accepts +/-.020 in. Axial shaft play
  • Off-axis mounting tolerance of .010 in.
  • 100 to 360 cycles per revolution (CPR)
  • 400 to 1,440 pulses per revolution (PPR)
  • Single +5V supply

See more info below

Configure the E4P

The E4P has reached its End of Life (EOL) and is no longer available for purchase. See E4T for replacement product information.

The E4P is no longer available for purchase.

E4P Product Description

Restriction of Hazardous Substances

The E4P miniature reflective encoder is designed to provide digital quadrature encoder feedback for high volume applications with limited space constraints. The E4P version utilizes an innovative, patented push-on encoder disk which accepts shaft diameters of 2mm to .250".     

The E4P reflective encoder is the leader for high quantity OEM applications, but the E4 is the ideal choice when a set-screw encoder disk encoder is required (see the E4 page). 

The E4P miniature encoder base provides mounting holes for two #3-48, length 1/4" or two M2.5x.45mm, length 6mm screws on a .586" bolt circle. When  mounting holes are not available, a pre-applied transfer adhesive (with peel-off backing) is available for "stick-on" mounting.

The encoder cover is easily snapped onto the base and is embossed with the connector pin-out.

The E4P reflective series encoder can be connected by using a (high retention 4-conductor snap-in polarized 1.25mm pitch) connector. Mating cables and connectors (see the Cables / Connectors web page) are not included, and are available separately.

Product Specifications

View here or download the specifications


Vibration (5Hz to 2kHz) 20 G
Max. Relative Humidity 90 %
Storage Temperature -40 to 100 C
Operating Temperature -20 to 100 C
Electrostatic Discharge, IEC 61000-4-2
Single-ended (S-option)
Differential (D-option)

± 8
± 15



Max. Shaft Axial Play ± .020 in.
Max. Off-axis Mounting Tolerance ± .010 in.
Max. Acceleration 250000 rad/sec²
Mounting Screw Size
Default (D-option base)
Metric (M-option base)

#3-48 x 1/4"
M2.5x.45mm, length 6mm
Screw Bolt Circle Diameter .586 ±.002 in.
Axial Length of Codewheel .270 in.
Required Shaft Length (1) .375 to .395 in.
Mounting Screw Torque 2-3 in-lbs
Technical Bulletin TB1001 - Shaft and Bore Tolerances Download

(1) Includes axial play.

Single-ended Electrical

Supply Voltage 4.5 5.0 5.5 V  
Supply Current   21 27 mA no load
Low-level Output     0.4 V IOL = 6 mA
High-level Output 2.4     V IOH = -1 mA
Rise Time   500   ns CL = 25 pF, RL = 2.7 kΩ
Fall Time   100   ns

Differential Electrical

Supply Voltage 4.5 5.0 5.5 V  
Supply Current   23 29 mA no load
Single-Ended Output Voltage High  4.75 5.0   V Min. @ 25mA load, Typ. @ no load
Single-Ended 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     1300 ns

Phase Relationship


Symmetry, S 180 ± 16 180 ± 75 electrical degrees
Quadrature Delay, Q 90 ± 10 90 ± 60 electrical degrees

(1) A leads B for clockwise shaft rotation, B leads A for counter clockwise shaft rotation viewed from the cover/label 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 hole in the cover for the shaft to pass through:

  • For shaft diameters of 1.5mm to 1/8", a 0.170" hole is supplied.
  • For shaft diameters of 5/32" to 1/4", a 0.295" hole is supplied.

M-option (Metric Mounting Screws)

Provides alternate metric M2.5x.45mm, length 6mm screws. When M-option is NOT specified the default is #3-48 x 1/4" screws.

T-option (Transfer Adhesive)

When mounting holes are not available, a pre-applied transfer adhesive (with peel-off backing) is available for "stick-on" mounting. Use the centering tool (above) to position the base. T-option specifies transfer adhesive.

Before installation, cleaning the mounting surface with alcohol is recommended to remove dust and oil.


1. Centering Tool

The centering tool is only included with the -3 packaging option. It has to be ordered separately for other package options.

Part #: MCTOOL - (Shaft Diameter)
Description: This reusable tool provides a simple method for accurately centering the E4P base onto the shaft. A centering tool is highly recommended when using the T-option transfer adhesive.

2. Spacer Tool

A spacer tool is included for all packaging options.

Part #: SPACER-E4P
Description: This reusable tool is used to properly space the codewheel from the encoder.

Product Change Notifications

Title Date Description Download
E4, E4P, S4 - PCN 5741 05/09/2016 As part of our on-going product lifecycle management process, we have identified products that will be transitioned to an "End-of-Life" status. Products targeted for end-of-life may be available for a last time buy option prior to being made obsolete, however quantities are limited and special requirements may apply.  Download
E4 - E4P - S4 Update - PCN 1014 11/29/2011 We have modifed the E4, E4P and S4 product lines in order to improve the performance and durability of the encoder. Changes include new molds for the plastic base and cover parts with an over-molded bushing in the S4 base, a new SMT connector (compatible with current mating connector)and a modified PCB profile to accommodate the new connector and plastic part modifications. Download

Additional Information

Product Notes

  • Cables and connectors are not included and must be ordered separately.
  • US Digital® warrants its products against defects in materials and workmanship for two years. See complete warranty for details.

Downloads Available




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