S4T Miniature Optical Shaft Encoder

S4T Features

  • Small size
  • Low cost
  • High retention snap-in polarized connector
  • -20C to 100C operating temperature
  • 100 to 1,000 cycles per revolution (CPR)
  • 400 to 4,000 pulses per revolution (PPR)
  • 2 channel quadrature TTL square wave outputs

See more info below

Configure the S4T

S4T Product Description

Restriction of Hazardous Substances

The S4T miniature optical shaft encoder is a non-contacting rotary to digital converter. The S4T contains an LED light source, monolithic photo detector and mylar disk. The S4T encoder is available with a shaft bushing or ball bearings for motion control applications, or with shaft torque designed to feel like a potentiometer for front-panel manual interfaces. The encoder converts real-time shaft angle, speed, and direction into TTL-compatible quadrature outputs without index.  It operates from a single +5VDC supply.

The S4T uses 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


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

± 12
± 7 

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


Specification Sleeve Bushing Ball Bearing
Max. Acceleration 10000 rad/sec² 250000 rad/sec²
Max. Shaft Speed 100 rpm 15000 rpm for CPR < 500
((6 x10^6) / CPR) rpm for CPR ≥ 500
Max. Shaft Torque 0.5 ±0.2 in-oz (D-option)
0.3 in-oz (N-option)
0.05 in-oz
Max. Shaft Loading 2 lbs. dynamic
20 lbs. static
1 lb.
Bearing Life > 1000000 revolutions L10 = (22/Fr)³ *
Where L10 = bearing life in millions of revs, and
Fr = radial shaft loading in pounds
Weight 0.48 oz. 0.43 oz.
Max. Shaft Runout 0.0015 in. T.I.R. 0.0015 in. T.I.R.
Max. Panel Nut Tightening Torque 20 in-lbs 20 in-lbs
Technical Bulletin TB1001 - Shaft and Bore Tolerances Download

* only valid with negligible axial shaft loading.

Phase Relationship


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

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

Single-ended Electrical

Supply Voltage 4.5 5.0 5.5 V  
Supply Current   25 30 mA CPR ≤ 500, no load
  34 42 mA CPR > 500, no load
Low-level Output     0.4 V CPR ≤ 500, IOL= 8 mA
CPR > 500, IOL= 5 mA
  0.035   V no load
High-level Output 2.4     V CPR ≤ 500, IOH= -8 mA
CPR > 500, IOH= -5 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 CPR ≤ 500, no load
36 44 mA CPR > 500, 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     20 ns


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

Product Change Notifications

Title Date Description Download
PCN 7163 - ED3 Firmware Update 6/30/2014

As part of our ongoing continuous improvement efforts, US Digital is implementing a firmware change to the ED3 Digital Encoder Display.
Firmware version 2.30 includes the following updates:

  • Supports up to 2kHz PWM, as available on the new M3K series of magnetic encoders.
  • Ability to return all parameters to the original factory settings.

Part Numbers Affected:

  • ED3-S, ED3-D
PCN 4464 - CE - RoHS 6/30/2014

US Digital is aware of the increasing attention to world-wide environmental regulations, specifically with regard to the need for hazardous substance restrictions in electronic components and systems. As of July 10th, 2014 US Digital will now be CE Marking certain products inline with compliance under RoHS Directive (2011/65/EU). In order to achieve RoHS Compliance, the products will not contain more than the acceptable levels of the listed restricted substances within the RoHS 2011/65/EU directive.

Part Numbers Affected:

  • ED3
  • USB4
  • QSB
  • MD2S
  • PS-5, PS-12, PS-24, PS-48 (Power Supplies)
  • PE

For the part numbers listed above, US Digital cannot confirm that they meet Low-Voltage and EMC Directives and for that reason US Digital cannot support shipping those products / product families into the CE required countries (For Example countries in the EU). Those products can still be shipped to Non-CE required countries with a Statement of Material Conformance to the RoHS Directive 2011/65/EU, in place of a RoHS Compliance Declaration.


Additional Information

Product Notes

  • Cables and connectors are not included and must be ordered separately.
  • For ordering information please see the Compatible Cables / Connectors section above.
  • View Shaft and Bore Tolerances - TB1001

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

    Related Products & Accessories

    The following are related products for the S4T

    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. Shaft

    3. Output

    4. Torque

    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...

    S4T Pricing

    Quantity Unit Price
    1 $65.00
    5 $60.00
    10 $57.56
    50 $55.12
    100 $52.68
    Over 100 Call for Quote
    Quantity Unit Price Subtotal
    $65.00 $65.00

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


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