TT Sensor Isolater

Thought Technology Ltd, Canada
Model: T9405AM


  • TT Sensor Isolator is a four channel optical isolator that provides isolated analog outputs to data acquisition systems from the Thought Technology sensors that make human skin contact.
  • It is available with stripped wires at the end of a 48” (120 cm) cable. Multiple isolators can be stacked for additional isolated channels.


1. Overview

There are two parts of the Sensor Isolator circuit which are isolated from each other:

  • the examinee-applied part.
  • the mains-connected part.


To operate the Sensor Isolator, each area requires a separate power source:

Client-applied area

  • 9V battery (standard PP3)

Mains-connected area (powered from either of the two inputs)

  • 9VDC power adaptor
  • 9VDC via DB-15 from external system

The Sensor Isolator has 4 inputs. These inputs can be connected to any Thought Technology sensors, such as, but not limited to, EMG, EKG or EEG sensors.


The Sensor Isolator has 4 outputs. The output range is 2.8V ± 1.5V.

These outputs can be connected to a data acquisition system in two ways:

  • via the two stereo jacks, or
  • via the DB-15 connector (interface cable provided with the unit).

2. Overview

All of the outputs are on the same circuits and the grounds are connected together :

  • If connecting several outputs to the same device, only one ground connection may be required.
  • If connecting outputs to more than one device ensure that no significant voltage exists between device grounds. Otherwise ground loop currents could flow through the Sensor Isolator, which could affect signal integrity or, in extreme cases, damage equipment.

2.1 Jacks

The jacks of the Sensor Isolator are 3.5mm stereo female mini-jacks.

electrical graph


Jack #1 is connected to Output #1 and #2 plug1
Jack #2 is connected to Output #3 and #4 plug2

2.2 DB-15 connector

The DB-type output connector of the Sensor Isolator is a DB-15 female.

plug input

NOTE: each interfaced system will require its own cable.
Therefore we provide only a cable with BNC connectors or the pigtail cable, which are the most common ones.



1. Power

  • 1.1 Powering the Examinee-Applied Area

The examinee-applied area is powered by a 9V battery.

Open the battery door on the back of the unit, by applying a gentle pressure and pushing it in the direction shown by the arrow:

battery door


  • 1.2 Powering the Mains-Applied Area

The mains-applied area can be powered either by the provided power adaptor or by the interfaced system via the DB15 connector.

Connect the power cable to the power connector located on the mains-applied area front panel.

power cord

No switch needs to be turned on.

For powering via the DB15, please read the previous section regarding the DB15 connector.

2. Cables

Here is an overview of the set-up.


2.1 Connecting a Sensor Cable

When connecting a sensor to the Sensor Isolator, make sure to properly line up the guiding dot on the top of the plug with the notch in the device’s input socket.

sensor insert

2.2 Connecting a DB-15 cable


The DB15 connector is located on the mains-applied area front panel.

audio jack

The audio jacks are located on the mains-applied area front panel, between the power connector and the DB15 connector


Size : 5.7 x 3.6 x 1.2 in (14.5 x 9 x 3 cm)
Weight : 180g
Isolation Voltage : 4.5kVrms
Voltage Input Range : 2.8V ± 1.5V
Bandwidth : 0 – 1kHz
Voltage Output Range, normal : 2.8V ± 1.5V
Voltage Output Range (possible) : 0 – 9V
(connected device should
tolerate this range)
Input impedance :  1.81MΩ
Output impedance :  110Ω
Accuracy :  Gain: ±0.1%
Offset: < 1mV
Noise :  <100μV RMS
Temperature range (operating) :  10 – 40 ˚C
Crosstalk :  < -90dB or better
Power Supply :  Isolated area
Examinee-applied part: 9V Alkaline battery (6LR61)
Battery Life: 10 hours typical
Low battery threshold: 7.25V
Mains-connected part: 9V AC adapter


GlobTek GTM41076-0609 : 6 Watts, Wall Plug-In, Switch mode
Power Supply, Medical, Class II
Input Voltage : 100-240 VAC
Input Current : < 0.5 A RMS MAX
Input Frequency : 47 – 63 Hz
Output Voltage : 9V
Output Current : 0 – 0.66A
Output Power (Rated) : 0 – 6W
Safety Approvals : UL60601-1, CUL to 22.2 No. 601.1-M90, INNOVA BAUART to EN60601-1, CE
CLASS II, PSE to J60601-1, CB REPORT, CTICK to AS/NZ 60601-1, CCC
Restriction of Hazardous Substances (RoHS) : Complies with EU 2002/95/EC
and CHINA SJ/T 11363-2006
Operating Temperature : 0°C to 40° C
Storage Temperature : -40°C to 80° C
Humidity : 0% to 90% Relative Humidity