2014-10-12 (Su) Adjustable tDCS

A 4K6 Ohm resistor and several 5K Ohm trimming pots were purchased from a surplus store. The 4K6 Ohm resistor was to ensure a minimum resistance value so current could not exceed the 2mA set point. The trimming pots were purchased in case the 4K6 Ohm resistor was not a good fit. The 4K6 Ohm resistor was soldered in series with the 20K Ohm pot and hooked up to the milliammeter set to measure short circuit current. The highest reading was 1.5mA.

 Resistors purchased

4K6 Ohm resistor in circuit

One of the trimming pots was adjusted to 4K57 Ohms and soldered into the circuit but the same result was found. The trimming pot was readjusted until 2mA was the highest obtainable reading and the accessible pot could be adjusted to change the output from 0.5mA to 2mA. An animated picture was made using a remote shutter to take pictures. The picture series was animated with GIMP.

Trimming pot adjusted to 4K57 Ohms

Showing the circuit cannot exceed 2mA

To do:
  • Update schematics
  • Update spreadsheet
    • Resistor
    • Potentiometer
    • Potentiometer knob
  • Order parts
  • Create assembly manual
  • Test and verify safety

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