2014-10-13 (M) Adjustable tDCS

The adjustable tDCS was set to the lowest allowable amperage and verified on the milliammeter. The tDCS Unit was also attached to confirm the milliammeter's functionality. The felt electrode sleeves were saturated with salt water and applied to the same locations as tested with the tDCS Unit on 2014-10-06 (M) . The pinching sensation was faint and disappeared within five seconds. The reading of the milliammeter showed 0.58mA flowing. the tDCS Unit was attached to the milliammeter without disturbing the electrodes and showed a reading of 1.61mA.

 Lowest amperage rating in a short circuit condition

Highest reading while using electrodes applied to body

Electrode on arm

Electrode held to head

Brainstorming was done as to why devices operating on the same technology would have different results. The 9V battery from the unit was retested and registered only 5.85V. A fresh battery replaced the one inside and and the milliammeter showed 2.75mA. This meant the potentiometer settings were adjusted for a dead battery. The trimming pot was adjusted until the maximum rating obtainable by the unit was 2mA. The potentiometer was measured and found to be 4K75 Ohms.

Short circuit condition with fresh battery

Reading of potentiometer used for safety

The electrodes were reattached to the milliammeter and body. The pinching sensation was strong so the test was discontinued. The current reading showed 0.82mA pared to 1.81mA from the tDCS Unit with the electrodes in the same position.

Maximum current from prototype

To do:
  • Compare to commercial unit
  • Update spreadsheet
    • Resistor
    • Trimming potentiometer
  • Order parts
  • Create assembly manual

 Journal Page 1

Journal Page 2

The rest of the posts for this project have been arranged by date.

A list showing of all the final posts of COMPLETED projects.

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